A photography book is its own unique medium, of course, involving aesthetic considerations beyond those of the individual images it contains. Its success is in the sum of its parts -- picture choice and sequencing, sizing and pacing, production values.This year's best books go way beyond monographs and photo histories. Publishers are taking more chances to catch the buyer's eye, and not just with big, elaborately packaged tomes. This year we saw everything from photographic board books, a format that brings back memories of childhood, to diminutive volumes that make a virtue of their preciousness. (One of these, Kadir van Lohuizen's 5x5-inch Diamond Matters, has a rhinestone embedded in its cover.) Even Aperture, which can always be counted on for cutting-edge photography books, has produced its largest volume ever, Richard Misrach's handsome, 17x24-inch On the Beach.