Don’t Sleep, There are Snakes.  By Daniel L. Everett.
 
Daniel L. Everett spent years in the Amazon studying the Pirahã, a tribe of about 300 people who live in several villages along the Maici river.  He was funded by SIL, the Summer Institute of Linguistics, a Christian missionary organization that concentrates on languages with relatively few speakers. The goal of SIL missionaries is to translate the Bible into these languages.
 
With the Pirahã, Everett found himself in missionary Hell and linguist Heaven. 
 
Missionary Hell, because the Pirahã were perfectly content with their lives.  There was nothing that Christianity could offer them that they valued above what they already had. And as his missionary mentor said “You gotta get ‘em lost before you can get ‘em saved.” (Page 266.)  In fact, the Pirahã ended up converting the missionary, rather than the other way around. 
 
Linguist’s Heaven, because the Pirahã language offers a challenge to some of the dominant theories of linguistics. It lacks a feature called “recursion” – the ability to put one sentence inside of another - and current theories argue that recursion is not only vital to language, but is “the unique component of human language” (page 228).
 
Everett’s linguistic discoveries made him famous – and his loss of faith apparently cost him his wife. He writes with humor and insight on his life in the Amazon and how language and culture interact .  (He also writes a few chapters at the end on linguistics and recursion – you can skip those if you’re not interested, without missing much of interest to those not passionately interested in linguistics or scientific infighting.)

Where does the title come from? "Don't sleep, there are snakes" is the translation of one of the Pirahã phrases for "good night".
 
Recommended for science buffs, language fans, and anyone who is curious about how others live.