Inventor-entrepreneur William Lear, number one exponent of the steam system for automobiles, may be the saving of us all. While Lear crisscrosses the country, exhibiting his turbine to industry and government, he also supervises ongoing corrections, implementations and efficiency problems at headquarters, an Air Force base he bought near Reno. Mr. Lear, nearing seventy, has an astonishing history of accomplishment. He was responsible for the first car radio, pioneered in early radio refinements, and development of the automatic pilot, created the Lear jet, and holds 135 patents. With public outcry against the polluting gas engine, and heel-dragging by Detroit and Washington, steam seemed the very world to conquer. Lear's biographer makes some attempt to follow his subject's Chicago-poverty to riches story -- four marriages, three divorces, restless moves and gambles, one-jumpmanship philosophy -- but he soon plunges into the very recent steam saga, setting down minute by minute crises of a man who always seems to be talking into six phones at once. Cool winds from Washington and hot blasts from Detroit merely raise Lear's own steam gauge. ""We'll drive (our) car up the White House steps. Maybe then we'll get their attention."" Mr. Boesen seems as much in a rush to set it all down as Lear is to gun his motors, and it's all rather raggedy reading. But the savvy reader will undoubtedly be pleased by the detail on such matters as the new engine's fuel (Learium) and a valve-by-screw explication of Lear's engine. It may not be pleasant to know Mr. Lear but this is potentially popular mechanics.