Hill Farms and Padi Fields: Life in Mainland Southeast Asia (A Spectrum book)

Although this book is somewhat out of date (first published in 1965), it continues to be a good general introduction for students of Southeast Asian societies. There are two major drawbacks in my opinion -- first, as I said, the book is out of date since the many years of warfare in the region have had a profound effects on the peoples in this region. Second, the author devotes only one chapter to the numerous hill tribes. The book is geared toward state-level societies in the lowlands. At any rate, the reader will come away with a good general understanding of state-level societies in mainland Southeast Asia. It's a good starting point for further study.