I've often said (eg) that in seeking to understand Islam you need to read the core doctrines and these are three: (1) the Koran, (2) the Hadith (sayings and actions of Muhammad) and (3) the Sirah (or life of Muhammad).
I've never labelled these a "Trilogy", though I wish I'd thought of this earlier. Or perhaps even -- though more provocatively -- a "Trinity": provocative because Islam abhors the Christian Trinity, the doctrine of the Father the Son and the Holy Ghost. To Islam, that's the worst kind of blasphemy, for nothing can be associated with the one God, Allah. To associate others with Allah is shirk, worse than murder and subject to death under Sharia law.
Anyhoo... I just came across this article, "A Taste of Islam", which talks of the "Islamic Trilogy": the same three I mention above.
Read it all, it repays careful study.
ADDED (7 November 2026): the link above no longer works. The book the article referenced is “A Taste of Islam” by Bill Warner.
A quote:
I sat down and reread the Koran, read the Sira (Ishaq and Al Tabari), read the Hadith (Bukhari and Muslim). These are the absolute foundational texts of Islam, the source code, the DNA. I was following Sun Tzu’s advice; know your enemy and attack your enemy’s strategy.And that's even if you limit "your enemy" to Al-Qaeda-type jihadis, for they are most certainly motivated and justified by the Trilogy.
See the excellent and eye-opening "The Al-Qaeda Reader" for example.
BTW: My Koran I’d the Penguin edition by N.J. Dawood. There are plenty of other translations online.
The Sirah I've read is that of Ibn Ishaq; the standard reference on Muhammad’s life. The Hadith, or sayings of Muhammad, that I have read are those of Bukhari, considered the most authoritative. Those of Muslim mostly repeat Bukhari.
If you want to know about Islam, and not what its apologists (or indeed its critics) tell you, then you must read the Trinity of Islam, starting with the Koran.
