So far I've been disappointed by the "functional X" books.. Probably because I've read SICP and much of the "functional" books just repeat the same patterns over and over.. i.e. memoization, closures, map, reduce, etc. Still, I'm a sucker for these books and I'll gladly buy it. Hopefully I'll learn a thing or two.. and if I do so, I'll be more then happy to share the word about it! : )