Interesting book, mostly on Algerian Islamicist extremism overseas and its links with extremists from other national groups. Sifaoui is an anti-Islamicist journalist from North Africa. The book is less about al-Qa'ida per se than about the Algerian Islamicist networks, but given the informality of 'al-Qa'ida', it is the more meaningful for it.
A book that goes well with this book is Abd Samad Moussaoui's "Zacarias Moussaoui, mon frère" (translated as "Zacarias Moussaoui: the twentieth man?" in the USA and as "Zacarias Moussaoui: The making of a terrorist" in the UK). Moussaoui, the brother of a French-Moroccan arrested immediately after 9/11, tries to explain why he thinks his brother became a terrorist. Thought-provoking.