I'm now enjoying The California Gold Rush and the Coming of the Civil War by Leonard Richards, a 2007 book. Excellent coverage of David Broderick and David Terry. It's the best book on San Francisco in the 1850 since The Rivals: William Gwin, David Broderick, and the Birth of California by Arthur Quinn from the mid 1990s.
Both books read like novels. It is a great wonderment to me that authors and publishers continue to find new things to communicate about that fascinating time.
Another book of that period I recently read was Colonel John W. Geary in the Mexican War and California in '49 by his relative Paul McClellan Geary, a distant relative who served as mayor of Antioch retaining the family tradition of providing mayors to California cities. This is a dreadful book in serious need of editing. The only worthwhile chapter is a ringing defense of Mayor Geary against the slander of Hubert Howe Bancroft. Unfortunately, a recent book on San Francisco history relied on Bancroft for his sketch of Geary rather than exploring other sources. John W. Geary was the only mayor of San Francisco to have served as governor of Kansas and Pennsylvania and to have attained the rank of general in the Civil War.