This book records the teachings of 12 Theravada Buddhists, mostly famous ones in their own societies: Achaan Chaa, Mahasi Sayadaw, Sunlun Sayadaw (via a disciple), Achaan Buddhadasa, Achaan Naeb, Achaan Maha Boowa, Taungpulu Sayadaw, Mohnyin Sayadaw, Mogok Sayadaw (via a disciple), U Ba Khin, Achaan Dhammadaro, and Achaan Jumnien. These are basically the most famous meditation instructors in Myanmar (Burma), Thailand and Laos. If you want to learn about Theravada meditation, either for scholarly reasons or to practice, you can't do better than this book without learning their languages.
However, I think it represents a sort of elite perspective on Theravada Buddhism. Many practitioners don't share exactly the spiritualities expressed by these teachers, and I think their practices and beliefs (some would say superstitions) are an important and valuable part of Theravada Buddhism, not to be neglected by either scholars or practioners.
This book although now a little dated, is still brilliant.Here in one book are the many diverse strands of Theravada Meditation, the Thai Forest Ajahns & the Burmese Vipassana Sayadaws are present. The material covers a very broad spectrum of Teachings & approaches. I am loving reading this book.