Al-Jafr is a mystical Shia holy book compiled, according to Shia belief, by Ali and inherited by him from Muhammad. Al-Jafr is composed of two skin boxes in which were kept various books of the past Prophets and the books inherited from Muhammad, Ali and Fatimah to the Ahl al-Bayt, with each new Imam receiving them from his dying predecessor Imam, as well as the armour and weapons of Muhammad.
Ashkar was one of the sources and origins of knowledge acquired by the 12 Imams and Imam Ja'far al-Sadiq took pride in having possession of al-Jafr, that comprised the hidden knowledge of Muhammad. The later Imams were accustomed to refer at times to the sacred and secret book of al-Jafr, which was left in their keeping by Ali and belief in the existence of al-Jafr with the Imams was firm, according to the Shia. 
The material of al-Jafr is parchment for writing made from animals' skin for which the word "Jafr" can variously mean; numerical symbolism, science of numbers, numerical symbolism of letters, numerology, science of letters, alphabetical symbolism or divination. The prefix "al" means the".
The contents of al-Jafr include:
- Secret teachings for the 12 Imams.
- Knowledge of the past and future events, including the names of every king who would rule on earth.
- The knowledge of Muhammad, the past Prophets and the 12 Imams. 
- The original Injil (holy book of Jesus), the original Torah (holy book of Moses), the original Zabur (holy book of David), the original Suhuf Ibrahim (Scrolls of Abraham) and the knowledge and history of the Prophets, life happenings, and other special mystical matters.  These are all contained in one part of al-Jafr called al-Jafr al-Abyadh (the white al-Jafr). Al-Jafr al-Abyadh has 14 portions and each portion has 14 divisions.
- A bag that contains the armour and weapons of Muhammad, including the sword Zulfiqar, and the Islamic rules, directives and matters about and involving wars.  These are all contained in the other part of al-Jafr called al-Jafr al-Ahmar (the red al-Jafr).
- The knowledge of the Israelite scholars.
Evidence of al-Jafr’s existence
The following are hadith evidences of the existence of al-Jafr:
- Shaykh Kulayni narrates from Abu al-Hasan that Imam Musa al-Kadhim (a.s) said, “My son, Ali, is the eldest and most beloved of my children. He reads Jafr along with me, while no one except the Prophet (i.e. Muhammad) and his successors look at it.”
- It has been narrated on the authority of `Abdullāh ibn Sinān that Imam Ja`far al-Sādiq said when we mentioned before him the activities of the descendants of Imam al-Hasan and also the al-Jafr: “By Allah I swear; we keep two papers made of skins of goat and sheep. These two papers comprise the dictation of the Messenger of Allah with the handwriting of (Imam) `Alī.”
- The Imam (a.s.) remained silent for a while and then said, "With us there is al-Jafr. Do they know what al-Jafr is?" I asked, "What is al-Jafr?" The Imam (a.s.) said, "It is a container made of skin that contains the knowledge of the prophets and the executors of their wills. It is the knowledge of the scholars in the past from the Israelites."
- A number of our people have narrated from Ahmad ibn Muhammad from Ali ibn al-Hakam from al-Husayn ibn abu ‘Ala’who has said that he heard abu ‘Abdallah (a.s.) say the following: "With me is the white Jafr." The narrator has said that he asked the Imam (a.s.) "What is in it?" The Imam (a.s.) said, "In it there is the psalm of David, the Torah of Moses, The Gospel of Jesus, the Books of Abraham, the laws that explain the lawful and unlawful.”
- Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ibn Mahbub from ibn Ri’ab from abu ‘Ubaydah who has said that the people from our group asked abu ‘Abdallah (a.s.) about Jafr and the Imam (a.s.) said the following: "It is the skin of a bull which is full of knowledge."
- The Imam (a.s.) said, “I swear by Allah that with me there are two books in which there is the name of every prophet and the name of every king that would rule on earth.”
- Ali ibn Ibrahim has narrated from Muhammad ibn ‘Isa from Yunus from the person that he mentioned from Sulayman ibn Khalid from abu ‘Abdallah (a.s.) who has said the following. "The Jafr of which they speak certainly disappoints them because they (the Zaydis) do not speak the truth while Jafr does contain the truth. Let them bring to light therefrom the judgments of Ali (a.s.) and his rules of inheritance if they are truthful. Ask them about (the inheritance) of paternal and maternal aunts. Let them show the Mushaf of Fatima (a.s.). In it certainly there is the will of Fatima (a.s.). With it there is the Armaments of the Messenger of Allah. Allah, the Most Holy, the Most High, has said, "Bring me a Book, revealed before this Quran, or any other proof based on knowledge to support your belief, if indeed you are truthful" (Qur'an 46:4).
- A number of our people has narrated from Ahmad ibn Muhammad from Ali ibn al-Hakam from al-Husayn ibn abu ‘Ala’ who has said that he heard abu ‘Abdallah (a.s.) say the following: "With me is the white Jafr." The narrator has said that he asked the Imams (a.s.) "What is in it?" The Imam (a.s.) said, "In it there is the psalms of David, the Torah of Moses, the Gospel of Jesus, the Books of Abraham, the laws that explain the lawful and unlawful matters and Mushaf of Fatima (a.s.) in which, I do not think there is nay thing from the Holy Quran. In it there is all that people need us to do for them and so that we would not need any one else. In it there is information even about a lash, half of a lash and one forth of a lash and about the amount of compensation for a scratch caused to someone. "With me there is the red Jafr." The narrator has said that he asked the Imam (a.s.), "What is in the red Jafr?" The Imam (a.s.) said, "In it there is the Armaments. It is because it only is opened for bloodshed. The owner of the sword opens it to kill." The narrator has said that ‘Abdallah ibn abu Ya‘fur asked the Imam (a.s.), "May Allah keep you well, do the descendents of al-Hassan (a.s.) know this? The Imam (a.s.) said, "Yes, I swear by Allah, they know it just as they know the night that it is night and the day that it is the day but jealousy and worldly gains cause them to act in denial and rejection. Had they sought the truth with the truth it would have been better for them."
- Ali ibn Ibrahim has narrated from his father from ibn abu ‘Umayr from ‘Umar ibn Udhayna from Fudayl ibn Yasar, Burayd ibn Mu‘wiya and Zurarah who have said that ‘Abdallah ibn ‘Abd al-Malik said the following to abu ‘Abdallah (a.s.), "The Zaydi sect and al-Mu‘tazali group circle around Muhammad ibn ‘Abdallah. Does he have any authority?" The Imam (a.s.) said, "I swear by Allah that with me there are two books in which there is the name of every prophet and the name of every king that would rule on earth. No, I swear by Allah, the name of Muhammad ibn ‘Abdallah is not in the list as one of them."
Al-Jafr is mentioned in the storyline of One Thousand and One Nights and an accurate explanation of al-Jafr is offered by Richard Francis Burton in The Supplemental Nights to the Thousand Nights and a Night (six volumes 1886 – 1888).
- Oxford Islamic Studies Online: Kitab al-Jafr
- Babylon: Islamic Dictionary
- Al-Islam.org: 'Aalim Network QR
- Imamreza.net: The Origins of the Knowledge of Ahl al-Bayt (A.S.), Source: Ahl al-Bayt (A.S.) in the Holy Qur'an and Hadith, By Ayatullah Muhammadi Rayshahri
- Imamreza.net: Collection of the Hadith by the Sh'ia
- Imamalinet.net: Ali the Magnificent, Compiled by Yousef N. Lalljee
- Imamreza.net: Imam Ali's Distinguished Place in Literary History
- Imamreza.net: Recognition of the Holy Imams (A.S.) in the Light of Traditions: Imam Ali Ibn Musa Al-Riza (a.s), By Ayatollah Sayyid Muhammad Reza Mudarrisi Yazdi
- Imamreza.net: Recordation of Hadith during the Imamate of Imam Baqir (A.S.) and Imam Sadiq (A.S.), By Sayyid Ali Al-Shahristani
- Henry Corbin, Trilogie ismaelienne, Paris: Maisonneuve, 1961, p. 30. The quotation is from Paul Kraus (Arabist), Jabir ibn Hayyan, v.2, Cairo, 1942, p.263. Reference may also be made to Corbin, "Le Livre du Glorieux de Jabir ibn Hayyan,” Eranos-Jahrbuch, v. 18 (1950), pp.75-87. See also Rajab Bursi, Mashariq Anwar al-Yaqin fi Asrar Amir al-Mu'minin (n.p, 1979), esp. pp. 18-38 (on this work see now Corbin, Rajab Borsi, and B.Todd Lawson, "The Dawning of the Lights of Certainty in the Divine Secrets Connected with the Commander of the Faithful by Rajab Bursi (d. 1411)," in Leonard Lewisohn, ed., The Legacy of Medieval Persian Sufism (London: Khaniqahi Nimatullahi Publications, 1992), pp. 261-276. In addition see Futuhat, v. 1, pp. 231-361: "al-bab al-thani fi ma`rifa maratib al-huru”' ; and the well-known manual on magic by Ahmad al-Buni (d.1225), Shams al-ma`arif al-kubra.
- Al-huda.al-khoei.org: Al-Huda News: OTHER COLLECTIONS
- Al-islam.org: 'Aalim Network QR
- Imamreza.net: Who Was Imam Jafar al-Sadiq(A.S.)? Chapter 2
- Shia-crescent.com: Defending the Imam of our time[dead link]
- CHAPTER NINETEEN: ON AL-REZA'S WORDS ON THE SIGN OF THE IMAM
- Imamreza.net: Recognition of the Holy Imams (A.S.) in the Light of Traditions: Imam Ali Ibn Musa Al-Riza (a.s): ‘Ithbat Al-Hudat, Vol. 6, p. 8: By Ayatollah Sayyid Muhammad Reza Mudarrisi Yazdi
- Kitab al-Kafi: Vol. 1, Hadith 635, Ch. 40, h1
- Kitab al-Kafi: Hadith 637 Ch. 40, h 3
- Kitab al-Kafi Hadith number 637 Ch.40, h 5
- Kitab al-Kafi: Hadith 641, Ch. 40, h 7
- Kitab al-Kafi, H 638, Chapter 40: Statements about al-Jafr, al-Jami‘ and the Book of Fatima (a.s.), h 4
- Kitab al-Kafi, H 637, Chapter 40: Statements about al-Jafr, al-Jami‘ and the Book of Fatima (a.s.), h 3
- Kitab al-Kafi, H 641, Chapter 40: Statements about al-Jafr, al-Jami‘ and the Book of Fatima (a.s.), h 7
- Supplemental Nights To The Book Of The Thousand And One Nights With Notes Anthropological And Explanatory, Volume 6, by Richard F. Burton, Part 8 out of 9
- Wikisource: The Tale of Attaf