Hal Rothman was a Las Vegas historian who wrote about the city with affection and clear eyes. Neon Metropolis (2002) is the best single-volume modern history of Las Vegas — how a small Mormon settlement and railway stop became the fastest-growing American city of the late twentieth century, and what it cost in environmental and social terms to pull off.
Rothman is particularly good on the post-Bugsy Siegel period — the corporate restructuring of the industry, the rise of the family-friendly mega-resort, the water politics with Lake Mead, the service-economy labor that runs the city. Read it before any visit if you want to understand why the place looks the way it does. Dense but accessible.