I've read on ton of books of art history and theory, and this one stands out as one of the best.
Through thirty years of friendship and discussions, Weschler traces Bob Irwin's career, from buffing car dashboards in high school to creating monumental gardens and installations in his old age. The benefit of this extended coverage is that we get to see how Irwin develops in every stage of his career, often as these developments are happening. We discover how relationships, environment, the art world, and philosophy influence Irwin's evolution and how each element manifests itself in his work.
Irwin typically deals with abstract, minimalist, and formalist art which is often considered "difficult", even by open minded art viewers. In these interviews, he extensively details his mental and physical process, offering an unparalleled look at just what goes into these works. He recounts staring at a canvas for weeks, trying to decide precisely where a line should go and what impact it will have on the finished work. Even if you don't find yourself mesmerized by the next Agnes Martin you come across after reading this book, you'll at least gain an appreciation of why some people find it interesting and what might have been going through the mind of the artist when he/she created it.
Part of what this makes this biography so compelling is that Irwin is an incredibly appealing character. Most successful artists are pigeonholed as shameless self-promoters or tortured geniuses. Irwin comes across as humble, brilliant, open minded, sincere, and indefatigably dedicated to his work. He seems like an art world version of Richard Feynman; the kind of curious guy you'd love to explore ideas with over a beer. He can talk about betting the ponies and Wittgenstein. He has a soft spot for Cadillacs but doesn't mind living a frugal, almost hermetic existence. He's fascinated by both the mind and the soul.
This book isn't a page turner (though Bob is an excellent story teller). It's really best savored and carefully considered. But, if you're interested in Irwin, abstract art, art theory, the artistic process, hope to increase your art appreciation, or are just looking for an interesting biography, this is well worth a read.