Geek Silicon Valley - dated but informative blend of history, context, and entertaining anecdotes about Silicon Valley.
DK Eyewitness Travel Guide: San Francisco & Northern California - an illustrated travel guide for San Francisco and Northern Carolina, not specific to tech.
History & Culture
Founders at Work - interviews with the founders of Silicon Valley startups like PayPal, Blogger, and TripAdvisor
Accidental Empires - historical account of Silicon Valley business from when Steve Jobs and Bill Gates started their companies.
Chaos Monkeys - chronicles a founders experiencing selling a company and working at Facebook
Disrupted - a humorous account of the older generation Dan Lyons working at a startup called HubSpot
Silicon Valley Map - an interactive map showing tech companies around the Bay Area
A Visitors Guide to Silicon Valley by Steve Blank
Bay Area Subreddit - discussion forum for locals
Where to See Silicon Valley - describes the subtly different places around the area, written by Paul Graham, founder of Y Combinator