The Big Four by Oscar Lewis (1938) — A collective biography of Leland Stanford, Charles Crocker, Mark Hopkins, and Collis Huntington, the Sacramento merchants who built the Central Pacific Railroad and became the most powerful men in California. Lewis writes without illusion: these were ruthless men who used Chinese labour, bribed legislatures, and manipulated land grants to accumulate fortunes that still shape California's institutions. The best single book for understanding how Sacramento's history connects to California's.
Grapes of Wrath by John Steinbeck (1939) — Technically about the San Joaquin Valley rather than Sacramento, but the Dust Bowl migrants who made it to California ended up in the same agricultural economy that Sacramento commands. The Central Valley's labour history — the same history César Chávez organised — runs directly through this novel.
The Sacramento by Julian Dana (1939) — A now-obscure but readable history of the Sacramento River from its headwaters to the Delta, following the river through Gold Rush, flood, and reclamation. Good for understanding how the physical landscape shaped the city.
California: A History by Kevin Starr (2005) — The condensed single-volume version of Starr's eight-volume California history series. Sacramento appears throughout as the hinge point between California's Gold Rush origins and its modern political identity. Starr is opinionated and readable, the opposite of textbook history.
Harvest: Field Notes from a Far Place by David Mas Masumoto (1993) — A Japanese-American peach and raisin farmer in the Central Valley south of Sacramento writes about the decision not to bulldoze his family's heirloom peach orchard. The book explains more about the Sacramento Valley's agricultural culture than any travel guide.