Inherent Vice by Thomas Pynchon

In 1970 LA, perpetually stoned private eye Doc Sportello gets tangled in a bizarre case involving his ex-girlfriend, a missing rich guy, and a shadowy group called the Golden Fang. The plot is hazy and psychedelic, a journey through a world of odd characters, corrupt cops, and the fading counterculture, more about the strange trip than a clear solution.