Whether it's a house in the Hamptons, an addition to a famous museum, or a new building for an Ivy League campus, contemporary architecture doesn't get any more coolly, cleanly serviceable than Gwathmey Siegel, the large firm that since 1965 has executed some of the most high-profile private and institutional commissions in the United States (with a few abroad). Gwathmey Siegel's history of concise, user-friendly innovation is well reflected here, in this comely monograph of 26 residential, corporate, academic and museum/arts-related projects spanning 35 years; per custom, it should be a hernia-inducing 10-pound hardcover, but instead is a near-palmsized paperback that still manages to convey the sweep and scale of GS's work in its excellent full-color photography with succinct annotations by firm founder Charles Gwathmey. Appropriately, the fun kicks off with the now-famous house and nearby studio Gwathmey designed for his parents in the Hamptons' Amagansett in 1965. Its basic principles of several levels, volumes, and niches intricately carved into a basic cube would play out again and again in the firm's work, which always manages to cunningly incorporate all sorts of technical solutions and aesthetic charms into volumes whose outer limits possess the simple, geometric logic of buildings that children have long fashioned from a few wooden