James M. Powell 
Crusades, The Kingdom of Sicily, and the Mediterranean [PDF ebook] 

In this collection of studies by James M. Powell, two related centres of attention can be seen. One is the campaigns undertaken by western Europeans in the eastern Mediterranean, chiefly in the late twelfth and thirteenth centuries — the Crusades — the reasons for them and manner in which they were organized and promoted. The other is the Kingdom of Sicily under Frederick II, himself a Crusader, and its society and economy, including its Muslim population. A characteristic feature is the author’s interest in ordinary participants and the attempt to get behind the generalizations of macro-historians to the extent that may be possible.