It is harmful to all who dare read its contents, although, currently, only Index is immune to the debihiltating effects of the grimoires, and with her perfect memory, allows her to serve as the vessel of the Index Librorum Prohibitorum. However, suspicions rise that she would rebel and become a Majin. This suspicion marks the catalyst for the events that would lead to the beginning of Toaru Majutsu no Index.
As stated, original grimoires are harmful as reading its contents would drive a human into insanity, and are even harmful to those that are trained to handle them.
According to Index, what is written inside of a grimoire is of a different world, and contradicts common sense, a knowledge that is far too alien to be safely comprehensible to any normal human. The knowledge that a grimoire possesses is "poisonous" in the sense that it is too "pure" for the human mind to handle and must be "watered down" – i.e. written in such a way that many of its meanings are obscured – in order for people to be able to read it without their minds being destroyed. Once a human is stained with the poison that is the contents of a grimoire, even inquisitors cannot remove the poison from the mind even after five years of baptism.
Types of grimoiresEdit
Oriana Thompson has also written up a form of disposable grimoires comprising flashcards, which allows her to use many different kinds of magic. Its drawbacks include its inability to cast the same spell twice with the same flashcard, so she has to keep writing grimoires in order to move forward; and its instability makes it destroy itself after a few weeks at best, as such it is not exactly a true grimoire.
Abilities and BehaviorEdit
Grimoire is practically "eternal" in the sense that it cannot be destroyed with current human methods (such as burning) and can only be sealed away. Original grimoires can apparently convert the words that are written inside their pages into magical code, which can be described as an auto-powered magic array or spell. The grimoires use the small amounts of energy released by nature or lifeforce as well as the weak magical energy released by humans, because of this attribute of acting like an auto-powered magic array, a grimoire can never be truly destroyed.
Index states however, that since she is unable to use her lifeforce to create mana (due to the restrictions on her made by the Necessarius), a grimoire manuscript that she writes down will not create such phenomenon, as such they can be destroyed, when normally a magician and even a normal human who releases magic energy through their lifeforce when writing a magic will have this problem.
The structure of a grimoire is compared to that of a Magic array, with Stiyl demonstrating how a magic circle written with words can end up having 2 or 3 additional lines surrounding the original circle, like sentences on a page.[Exact volume citation needed]
Grimoires are seemingly sentient enough to disclose its contents to people who desire information from it. Grimoires can apparently identify whether someone was a "reader" or "not a reader", and have the tendency to cooperate with those who would propagate the information with their contents.
As such, a magician could trick the decision-making capabilities of the grimoire under the belief that they could act as an evangelist for its knowledge. Regardless of this, the contents of the grimoire is still dangerous to anyone who reads it and those who attempt to take control of the grimoire. It is currently unknown if a grimoire is aware that they are dangerous to people.
If the grimoire judges its current owner to be unsuitable, it will kill him/her and seek out the next one, as shown in Volumes 15, when Etzali needed to protect Xochitl from her own grimoire  and in volume 19, when a grimoire actually killed it's wielder as he was inadvertently trying to prevent it's knowledge from being handed down .
One theoretical way to destroy a grimoire, according to Orsola Aquinas, is to write data that will force it to destroy itself into it. However, it is unknown if someone has successfully managed this, as the writer still needs to see the pages of the grimoire to actually write down the code, and even a mere glimpse of a grimoire is already dangerous.[Notes 1] Kamijou Touma also suggested the possibility that his Imagine Breaker would be able to fully destroy grimoires, although he has yet to make any attempt.
Aureolus Izzard's job before he met Index was to write up vaccines that can destroy grimoires for the Roman Catholic Church. It is unknown if the writer of an original grimoire can destroy their own creations.
It should be noted that when a magician has been enough skill, they can read the contents of a Grimoire and not suffer from its contamination, one of this cases was Aureolus 
Not unlike Saints, grimoires carries a somewhat heavy political pull, with it containing powerful spells as well as being indestructible, because of these, grimoires are sealed in their respective holding places such as libraries and cannot normally be stolen.
Grimoires are also used by the organizations keeping them to promote themselves, as with the case with the Roman Catholic Church displaying the Book of the Law to the public.[Notes 2] Furthermore, a lost grimoire could spell turmoil between the magic organizations, as what had occurred with Amakusa Christians being accused for stealing the Book of the Law, causing the Anglican Church, Roman Catholic Church as well as the Knights of England to take action.[Notes 2]
As such, magic societies will not simply leak the contents of the grimoires they keep for no reason, one of those rare reasons were to allow Index of Necessarius to memorize the grimoires for the purpose of reverse-engineering and neutralizing them, and with the 103,000 grimoires inside Index, there is a possibility that all magic in the world can be neutralized. Because of her status as a magic library, Index is reviled by magic societies for knowing the knowledge of the grimoires, knowledge that can be used against those who originally owned the knowledge before Index came along. As such, Index is being hunted by Magic cabals, and is feared by her own church.
List of GrimoiresEdit
As Index is a major character who holds 103,000 grimoires, it is only natural that these grimoires appear as a substantial part to the Toaru Majutsu no Index universe. These are a list of grimoires that have appeared so far in alphabetical order.
|Name||Notes and Description||First mention||Confirmed to be inside Index|
|Aztec Calendar Stone (暦石 Koyomi Ishi?)||The calendar stone was an Aztec calendar arranged in a circle. However, the Aztecs used two different forms of calendars at once and believed in the death and rebirth of the sun, so it was an incredibly complex thing to make. What was described on the inside of Xochitl’s skin took only the times that dealt with life and death from that calendar and then expanded on it with a religious dissertation. It contains the Times related to Life and Death and the Moon Rabbit records.||Toaru Majutsu no Index Light Novel Volume 15||No|
|Baopuzi (抱朴子(ほうぼくし) Baopuzi?, lit. "Dabokuko(Hōbokushi)")||It is a grimoire from China with a way to become an immortal written inside it. Within the book is the way to learn Rentanjutsu, it's said a person can create a miracle drug to cure any illness or curse using that technique.||Toaru Majutsu no Index Light Novel Volume 05||Yes|
|Book of Creation (Sefer Yetzira) (創造の書 Sōzō no sho?)||It is the title of the earliest existing book on Jewish esotericism, although some early commentators treated it as a treatise on mathematical and linguistic theory as opposed to Kabbalah. "Yetzirah" is more literally translated as "Formation"; the word "Briah" is used for "Creation".||Toaru Majutsu no Index Light Novel Volume 05||Yes|
|Book of Eibon (エイボンの書?)||As with the Necronomicon, it is a fictional grimoire created by Clark Ashton Smith, a close correpondence of H.P. Lovecraft, creator of the Necronomicon and of the Cthulhu Mythos. This and the Necronomicon are the most famous fictional grimoires in popular culture.||Toaru Majutsu no Index Light Novel Volume 01||Yes|
|Book of Hermes (Hermetica) (ヘルメス文書?)||The Hermetica are Egyptian-Greek wisdom texts from the 2nd and 3rd centuries CE, mostly presented as dialogues in which a teacher, generally identified with Hermes Trismegistus or "thrice-greatest Hermes", enlightens a disciple. The texts discuss the nature of the divine, mind, nature and the cosmos: some touch upon alchemy, astrology and related concepts.||Toaru Majutsu no Index Light Novel Volume 05||Yes|
|Book of M (Ｍの書?)||Is the mystical book that is referenced in the Fama Fraternitatis, where Christian Rosenkreutz receives the Book M from sages in the East, which supposedly contained the secrets of the universe, and which he subsequently translated into Latin.||Toaru Majutsu no Index Light Novel Volume 05||Yes|
|Book of the Dead (死者の書?)||Is the modern name of an ancient Egyptian funerary text, used from the beginning of the New Kingdom (around 1550 BC) to around 50 BC.||Toaru Majutsu no Index Light Novel Volume 01||Yes|
|Book of the Law (Liber AL vel Legis) (法の書?)||Is the currently undecipherable grimoire written by Aleister Crowley, said to be dictated to him by Aiwass, and said to end the age of Christianity if opened.||Toaru Majutsu no Index Light Novel Volume 06||Yes|
|Cannabalism Ritual Book (食人祭祀書 Shokujin saishi-sho?)||Toaru Majutsu no Index Light Novel Volume 01||Yes|
|Golden Bough (金枝篇 Kaneeda-hen?)||It is a wide-ranging, comparative study of mythology and religion, written by Scottish anthropologist Sir James George Frazer (1854–1941). It was first published in two volumes in 1890; and the third edition, published 1906–15, comprised twelve volumes.||Toaru Majutsu no Index Light Novel Volume 05||Yes|
|Fragment of the Rune Epitaph||A grimoire fragment derived from special runes from Alaska.||Toaru Majutsu no Index: Stiyl SS||No|
|Kinugyokutoshū (金烏玉兎集 Kin'ugyokuto-shū?, lit. Collection Book of the Moon and the Jade rabbit)||According to Tsuchimikado Motoharu, it is a legendary book on Onmyoudou that was passed from China. It has no connection to the similarly named Aztec record Moon Rabbit.||Toaru Majutsu no Index Light Novel Volume 04||Yes|
|Lesser Key of Solomon (Lemegeton) (ソロモンの小さな鍵（レメゲトン） Solomon no chīsana kagi?)||It is an anonymous 17th-century grimoire, and one of the most popular books of demonology.||Toaru Majutsu no Index Light Novel Volume 01||Yes|
|Momotarou (桃太郎 Momotarō?)||It is a popular hero from Japanese folklore. His name literally means Peach Tarō; as Tarō is a common Japanese boy's name, it is often translated as Peach Boy. Momotarō is also the title of various books, films, and other works that portray the tale of this hero. According to Index, it is a realy magic grimoire, camouflaged to look like a harmless fairy tale. She states there's actually no such person as 'Momotarou who was born from a peach. The correct interpretation of the story is that the peach that flowed down the River (as rivers were traditionally used as a metaphor as a boundary between Life and Death) is a forbidden fruit that lets people surpasses Life and Death. In Eastern culture, there is mention of a fruit of Immortality. Of course, it's the peach that the Queen Mother is protecting. The original Momotarou wasn't 'born out of the peach', but 'the grandpa and granny ate the fruit and became you. One can tell from this that this story is about the creation of an elixir of Immortality.||Toaru Majutsu no Index Light Novel Volume 05||Yes|
|Moonchild (クロウリーの書(ムーンチャイルド)?)||It is a novel written by the British occultist Aleister Crowley in 1917. Its plot involves a magical war between a group of white magicians, led by the protagonist Simon Iff, and a group of black magicians over an unborn child. In Toaru Majutsu no Index, it is a grimoire referenced by Stiyl Magnus, when trying to start the ritual that will erase Index's memory. The book contains a way to summon a spirit using an angel's binding technique.||Toaru Majutsu no Index Light Novel Volume 01||No|
|Nameless Book (ネームレス(無名祭祀書) Nemuresu (Mumeisaishisho)?)||Toaru Majutsu no Index Light Novel Volume 01||Yes|
|Necronomicon (死霊術書(ネクロノミコン) Shiryō-jutsu-sho (Nekuronomikon)?)||In reality is a fictional grimoire created by horror writer H.P. Lovecraft for his stories, it is unknown if the same applies to the Toaru Majutsu no Index universe. Seeing as it is one of the books stated that are contained within Index, it is assumed that their version of the Necronomicon is genuine in their universe. Index also states that the book is too famous and as consequence has a lot of imitations, which probably references the Simon Necronomicon.||Toaru Majutsu no Index Light Novel Volume 01||Yes|
|The Secret Doctrine (秘奥の教義 Hiō no kyōgi?)||The Secret Doctrine is a book originally published as two volumes in 1888, is Helena Blavatsky's magnum opus. The first volume is named Cosmogenesis, the second Anthropogenesis. It was an influential example of the revival of interest in esoteric and occult ideas in the modern age, in particular because of its claim to reconcile ancient eastern wisdom with modern science.||Toaru Majutsu no Index Light Novel Volume 05||Yes|
|Tetrabiblos (テトラビブロス Tetorabiburosu?)||(Τετράβιβλος) 'four books', also known in Greek as Apotelesmatiká (Αποτελεσματικά) 'effects', and in Latin as Quadripartitum 'four parts', is a text on the philosophy and practice of astrology, written in the second century AD by the Alexandrian scholar Claudius Ptolemy (c.AD 90–c.AD 168).||Toaru Majutsu no Index Light Novel Volume 05||Yes|
- ↑ Etzali under the guise of Unabara Mitsuki catches a glimpse of a grimoire that has replaced Xochitl's skin.
- ↑ 2.0 2.1 The Book of the Law being displayed for the public was of course fake, to give the Roman Catholic Church an excuse to hunt down Orsola Aquinas who can decode the Book of the Law, and pin her death on the Amakusa-Style Remix of Church.
- ↑ 1.0 1.1 1.2 1.3 1.4 Toaru Majutsu no Index Light Novel Volume 01 Chapter 2 Part 2
- ↑ 2.0 2.1 2.2 Toaru Majutsu no Index Light Novel Volume 15 Chapter 3 Part 11
- ↑ Toaru Majutsu no Index Light Novel Volume 15
- ↑ Toaru Majutsu no Index Light Novel Volume 19
- ↑ Toaru Majutsu no Index Light Novel Volume 09
- ↑ 6.0 6.1 Toaru Majutsu no Index Light Novel Volume 07 Chapter 2 Part 1
- ↑ 7.0 7.1 Toaru Majutsu no Index Light Novel 15 Chapter 3 Part 12
- ↑ Toaru Majutsu no Index Light Novel 19 Chapter 03 Part 10
- ↑ 9.0 9.1 9.2 Toaru Majutsu no Index Light Novel Volume 07
- ↑ Toaru Majutsu no Index Light Novel Volume 02 Chapter 3 Part 4
- ↑ Toaru Majutsu no Index Light Novel 07 Chapter 04 Part 2
- ↑ Toaru Majutsu no Index Light Novel Volume 05
- ↑ Contending for Faith ~ The Received Text ~: Once Delivered to the Saints Chapter 20 "Chritian Rosenkreutz" (Retrieved:2012/6/3)
- ↑ Toaru Majutsu no Index Light Novel Volume 04 Chapter 2 Part 5
- ↑ Toaru Majutsu no Index Light Novel Volume 01 Chapter 4