This book (says the introduction) was distilled from a series of talks Wallace gave as he led a retreat on Shamatha (a.k.a shi nay -- "calm abiding meditation") up in the Sierras, and it retains an informal, practical, nuts-and-bolts atmosphere. This isn't for people who want to speculate or theorize about the Dharma: it's for people who want to practice. I've been meditating for many years, but this is the first and still the only book I've actually used as part of my practice -- often before sitting down on the cushion I'll read a few pages of it, to remind myself of what I'm doing and why.
There's lots of useful advice here. Wallace talks about the art of practicing Shamatha as a sort of tuning the intensity of awareness-- too little intensity and you tend to sink into torpor, too much and you tend to follow distractions. He warns against practicing with too much grim determination, which can squeeze the joy out of it and make one sick of meditation. On down to the simple suggestion that if you're too sleepy during practice you should probably get more sleep.
Wallace is a distinguished scholar. He was for many years a monk in the Tibetan tradition, and he speaks from a deep reservoir of experience and teaching. But he's also a Westerner and (now) a householder, so that he understands the tribulations, and unexpected benefits, of practicing in this world of busy distractions and pressing duties. This book radiates a gentle kindliness and simplicity of heart. For me it's an endless source of comfort and inspiration to practice.