Depth of research and depth of feeling make the difference. This is a great biography not because Caro exposes Lyndon Johnson's ruthlessness, duplicity, and use of money, but because he reveals Johnson's mastery of detail, his impact on other lives, his genius as a hands-on politician. And in that context, Caro's ascription of Johnson's rise to the financial backing of Brown & Root, the Texas contractor, does hot ring wholely true--for at each stage, he demonstrates, Johnson created his own opportunities. The portrait of Johnson's upbringing in Texas' impoverished, isolated Hill Country, and of his boyhood emulation and adolescent rejection of his hero-politician/drunken-failure father, lays the groundwork for Johnson's towering insecurity, his lifelong need to exact "respect--and fear." Rather than go to college as his parents wished, he goes to California (that episode is demythologized); rather than be stuck in Johnson City, he goes to college--where "he began campus politics," started cultivating older men, "stole" his first election, became secretive, and announced (what Caro, ex post facto, perhaps overstresses) his intention to be president. Then, at an Austin high school, he coaches the debating team to the state finals. As the green, 23-year-old secretary to new, playboy congressman Richard Kleberg, he makes a science and an art of answering the mail; as "one of a thousand' congressional aides, he develops the "Little Congress," their organization, as a power base; as a political aspirant, he downplays Kleberg and plays himself up. In a few years, he has entree. And that's why, when a congressional vacancy occurs during his stint as Texas NYA director, he gets key backing for the nomination: someone is needed who (like the deceased) can get a shaky, make-or-break Brown & Root contract cleared. Caro shows Johnson winning that election, vote by vote, "on the forks of the creeks"; persuading rock-bottom Hill Country farmers to enlist in the Agriculture Department's Range Conservation program (and persuading the Department to make it worth their while); bringing electricity to the Hill Country farm wife still "hauling water and hauling wood." If a book so consistently engrossing can be said to peak, it's in the chapters on Johnson as the New Deal's most energetic congressman. But Caro is a believer and Johnson was a trimmer--and so we have the theme of betrayal, the most wrenching of Johnson's iniquities: he betrayed his father by misrepresenting him as a drunken ne'erdo-well; later he would betray his surrogate fathers Sam Rayburn and FDR. There is a serious, hitherto undisclosed romance; there are the promised particulars on Johnson's political legerdemain; there is always the testimony of intimates, and detail upon detail. One is appalled by Johnson--and awed.