The University of California has launched a reprint service that provides access to digitally scanned "rare, out-of-print, and hard to find books" from its library collections. You can purchase printed and bound copies of these titles. In addition, you can read hundreds of out-of-copyright books for free online.
Note that these electronic volumes contain images of each page. So what you see is the original typography (which may be hard to read), not generic flowing text (such as displayed in a device like the Kindle).
The UC LIbrary Reprints website has a handy search interface for finding books by author, title, category and description word. Here are just a few volumes related to California history and historical fiction that can be read online:
History of Santa Cruz County, California (1892).
Rezanov by Gertrude Franklin Horn Atherton (1906).
The founding of Spanish California by Charles E. Chapman (1916).
Three years in California, 1846-1849 by Walter Colton (1852).
A history of the College of California by Samuel H. Willey (1887).
History of early California journalism by Ralph S. Kuykendall (1918).
California, romantic and resourceful by John F. Davis (1914).
Glimpses of California and the missions by Helen Hunt Jackson (1914).
A brief history of astronomy in California by William Wallace Campbell (1913).
Stories of California by Ella May Sexton (1902).