Interesting that Feral House published that. The editor, Adam Parfrey, previously edited Apocalypse Culture, a collection of contributions from terrorists and cults of all political persuasions, including neo-Nazi associates of Charles Manson (Parfrey is linked to skinhead friends of Manson), the Red Brigades, the Black Muslims, and other lesser-known but even more extreme characters. To illustrate what I mean by "extreme", one of Parfrey's own contributions is called "Cut it Off: A Case for Self-Castration". Extremely sick people at that publishing house.
Admittedly, most of their literary output is bizarre, off-the-wall crap.
However, that book is worth reading.
It consists almost exclusively of primary source documents from the Islamic terror movement or their perceived nemeses, e.g., excerpts from Sayyid Qutb's works, diaries of foreign Chechen mercenaries, the document that motivated the assassination of Anwar Sadat, writings of Sadat himself, the memoirs of Glub Pasha, etc., etc...
In terms of being a primer on modern Islamic terrorism-and its sources-it's a fantastic resource.