Lenin's older brother, Alexander Ulyanov, is only a footnote in history. Hence, this book's subtitle seems an overly large claim. Pomper justifies it in a dual sense: Ulyanov's political and intellectual milieu contained important antecedents of the movement to follow, and his life's twisted tragic-heroic turn heavily shaped Lenin's personal psychology. In March 1887, on a date timed to mark the successful assassination of Tsar Alexander II six years earlier, Ulyanov and 14 others plotted the same fate for Tsar Alexander III. They never got to throw their bombs at the target, and Ulyanov was hanged two months later. The psychological reading that Pomper renders -- that Lenin, in some significant degree, made the revolution to avenge what the tsarist regime had done to his brother and his family -- may not be entirely convincing in the absence of direct testimony from Lenin or those who knew him. But the canvas that Pomper so richly fills with the details of Ulyanov's precocious teenage intellectual interests and his path from a preoccupation with zoology to revolution and, ultimately, to terrorism makes for very engaging reading.