Curious about the story that Musa al Sadr might still be alive in some dungeon of Gadaffi's (I refuse to spell that cur's name correctly by way of protest), I discovered this early book by Ajami, which turns out to be not only the most beautiful and evocative, but the most useful book I've read on the feeling of modern Arab, Iranian and Levantine politics, despite that it is 25 years old. So much hasn't changed, or is just now changing - in Iran, Libya and Egypt - that it is surprisingly apt. Most of all, the Vanished I. gives the most spacious and clearest explanation of the Shia outlook and experience that I've ever encountered (I've heard Ajami expound upon it here and there, but this is virtually a whole book about it. The book is most dated about Lebanon itself - but everything that has taken place since 1986 was set in motion by the main players in Ajami's account. I can't begin to summarize or crystallize what I now know about Sunni-Shi'a differences, but I assure you I am wiser about them.
One thing I can recount of which I was entirely unaware is that Persia is Shia only because of a dynastic change only 400 years ago - it was not "naturally" Shia, as I had always somehow stupidly assumed. And clerics and intellectuals had to be imported from what is now Lebanon to Shia-ize its population - much as areas of Europe were Catholicized or Protetestantized for similar reasons around the same time (did you know that northern Italy and Poland had big Protestant, even (the latter) Unitarian populations before the counter-reformation? So the link between Iran and Lebanon's (really Syria's) Shia was centuries old - and Al Sadr's family originated in the Lebanon, were "sent" to Persia in the 16th century, and he returned from Iran to Lebanon only in the 60s.
Also great is the portrait of Al Sadr himself - he is very much a sixties kind of guy - tall, big personality, got along wonderfully with other faiths. He is wonderfully in the mold of big clerics of that age - Rabbi Abraham Heschel, Father Ted Hesburgh, Bishop Pike, etc. The Lebanese loved him because he dressed well and had a sense of style, essential to success in Lebanese life - Ajami quotes someone who says that Musa Al Sadr was the first mullah he ever encountered whose shoes weren't dirty.
All in all, I'd say this is the second most beautiful and wise book on Arab religion and politics (well, Persianized Arab) after Doughty's Arabia Deserta.