Yoga. Somehow it became the workout flavor of the new millennium. It's hotter than Yogi Bear, yogurt, yo-yos, yo' mama, or anything else that starts with yo. So if you can't pretzel yourself into a posture that allows you to contemplate your own butt, you can at least own a whopping $75 coffee table book loaded with mostly full-page black and white photos of people who must kill at Twister. Yoga, which even offers an introductory chapter on the history of yoga, is a Yoga Journal Book, by Linda Sparrowe, with photographs by San Francisco-based advertising, fashion and portrait shooter David Martinez, who marks his debut book project with this effort.