Melvil Dewey (1851-1931) is known for his Decimal Classification system for libraries, but the system was only one endeavor in a feverishly ambitious life. The other Dewey - reformer, businessman, powerful state education officer, resort-empire builder - has long been obscured, as has the dark side of Dewey's personality. Drawing from years of archival research, preeminent Melvil Dewey historian Wayne A. Wiegand has produced the first frank and comprehensive biography of this enigmatic reformer. While providing richer background on Dewey's positive achievements than earlier, reverential biographies, Wiegand reveals his subject as one who was "driven, tense, often arrogant," who had "an obsessive need to control...and self-righteously denied his own racism and class prejudices.". Whatever Dewey's virtues and flaws, his influence on libraries and education was profound. To understand his life is to better understand these institutions - then and now - and the people who shape them.