In the scant hour I spent in the home of Galen Cranz, two things became hopelessly clear: One, 99 percent of chairs are terrible; and two, so is my posture. The good news: There are better ways to sit. The bad news: There is no such thing as a perfect chair. The really bad news is that most of us spend half our waking hours in chairs. And the really, really bad news is that the problem isn't my posture but a world that is not tall, sloped, adjustable, or active enough.

Galen Cranz wants to change all that. In The Chair: Rethinking Culture, Body and Design (Norton, 1998), this architecture professor takes us on a journey that begins with slouching pharaohs and ends in an ideal world that encourages no less than six postures in which to work: standing, sitting, lying, perching, squatting, and 'autonomous sitting' (on a stool). Along the way, Cranz explains why the ubiquitous canvas stroller makes babies spit up, why a soft, comfortable chair has nothing to do with real comfort, why the Last Supper took place lying down, why Northern Europeans call squat toilets Italian toilets (and why Italians call them Turkish), why one of the most famous modern chairs is actually awful to sit on, and why a secretary who uses a recliner threatens to upset entrenched power relationships in corporate America.

'We design them; once built, they shape us,' Cranz says of chairs. So important is the image of the right chair that aficionados have appropriated a Freudian phrase to describe the difficulty of choosing one: 'chair anxiety,' a common malady.

Like a tattoo for the middle classes, the chair reveals its owner through visual, sensual clues. The solid mission chair: permanence, warmth, and an implicit critique of mass production. And the sleek Barcelona chair: minimalism, transparency, disdain for tradition. Nothing wrong with transforming utility into art, of course, but Cranz says the aesthetic pleasure of the right angle and the pomp of the gilded throne have overshadowed the chair as sitting machine. The Barcelona chair collapses spines, promotes slipped disks, and is about as easy to get out of as a Kafka short story. Most chairs, Cranz laments, are four-legged monsters responsible for back problems, neck problems, and $70 billion annually in lost productivity.