Arriving in Mexican California in 1832, Thomas O. Larkin (1802-1858) expected to become a rich man-and he did: he became a successful merchant, financier, and land developer. Larkin also became the confidant of California officials, American consul to California, and secret agent of the president of the United States during the territory's transition from Mexican to American control. Harlan Hague and David Langum have uncovered a large body of new information, shedding light on many aspects of Larkin's personal life as well as on his business and diplomatic activities. Historians and general readers will welcome this full-scale biography of one of the most important men in the history of early California.