Residential Framing by William P. Spence (Sterling Publishing Co., 1994; 212/532- 7160). Softcover, 81/4x11, 288 pages. $19.95. Nearly every book on house construction begins with the familiar diagram of batter boards, strings, and plumb bobs defining the corners of a foundation. That same diagram is in William Spence's book, Residential Framing, too, but he explains the thought behind the design and the materials used better than other books I've read. It's another instance of the "beauty of simplicity" that reminds readers why they love building. After discussing the framing details that need to be incorporated into the foundation, Spence gets down to the nitty-gritty of his subject: how to build a house frame out of wood. Most contractors will probably postpone reading the chapters on the characteristics of wood and engineered wood products, tooling