The Book of Fatimah (A.S.)
Some anti-Shi'i booklets published by Wahhabis groups allege that based on Usul Kafi, Shia believe there is a Quran called "Quran of Fatimah"! This is a malicious accusation. There is no tradition in Usul Kafi saying "Quran of Fatimah". There are however, very few traditions in one chapter of Usul
Kafi which assert that Fatimah (AS) wrote a book (mushaf). The tradition states "The book of Fatimah". Surely Quran is a book (mushaf), but any book is NOT Quran. This allegation is as silly as saying "Quran of al-Bukhari" instead of "book of al-Bukhari"!
Also those few traditions in al-Kafi clearly state that there is NO single verse of Quran in the Book of Fatimah. This shows that the book of Fatimah is TOTALLY different than Quran. Of course, it was three time bigger than Quran in length.
In one tradition it said that Fatimah (AS), after the Prophet (S.A.W.) passed away, used to write what she was told that would happen to her descendants and stories about other rulers to come (up to the day of resurrection). Fatimah (AS) recorded (or asked Imam Ali to record) those information, which was kept in her family of Imams, and was called "The Book (Mushaf) of Fatimah". A tradition which follows this one clearly states that what is referred to by "The Book of Fatimah" is not a part of Quran and has NOTHING to do with Allah's commandments/halals/harams. It does NOT have anything to do with Shari'ah (divine law) and the religious practices. Let me give you some of those traditions: Abu Abdillah (AS) said: "... We have with us the Book of Fatimah, but I do not claim that anything of the Quran is in it." (Usul al-Kafi, Tradition #637)
Abu Abdillah (AS) also said about the book of Fatimah: "There is nothing of what is permitted and what is forbidden (al-Halal and al- Haram) in this; but in it is the knowledge of what will happen." (Usul Kafi, Tradition #636)
Abdul Malik Ibn Ayan said to Abu Abdillah (AS): "The Zaydiyyah and the Mu'tazilah have gathered around Muhammad Ibn Abdillah (Ibn al-Hasan, the second). Will have they any rule?" He (AS) said: "By Allah there are two books in my possession in which every prophet and every ruler who rules on this earth (from the beginning of the earth till the day of Judgment) has been named. No, by Allah, Muhammad Ibn Abdillah is not one of them." (Usul Kafi, Tradition #641)
"Mushaf" refers to a collection of "Sahifa" which is singular for "page". The literal meaning of Mushaf is "The manuscript bound between two boards". In those days they used to write on leather and other materials. They either rolled the writings -- what is known as scroll in English. Or they kept the separable sheets and bound them together, in what could be called as "Mushaf", a book in today's terms. The equivalent to the word book "Kitab" used to (and still is) refer to either a letter (e.g. of correspondence) or to an document that was written down or recorded. The Arabic word for wrote "Kataba" is a derivative of the same word.
Although the Quran is commonly called a "Mushaf" today, perhaps referring to its "collection" after it was dispersed. Quran is a Mushaf (book), but any Mushaf (book) is not necessarily the Quran! There is no Quran of Fatimah! As the above and many other traditions suggest, The book of Fatimah has absolutely no connection with Quran. This concept is commonly pulled out of context and published by anti-Shi'i groups due to their hatred toward the Followers of the Members of the House of Prophet (S.A.W.). I have seen it mentioned in a book printed by the government of Saudi Arabia.
What is also very important to recognize and understand is that belief in Mushaf Fatimah is NOT a requirement of BELIEF to the Shia. It is just few traditions which report such a thing. It is nothing crucial for us, nor any one (except Imam Mahdi) has access to it.