The Fabulous Furry Freak Brothers Omnibus by Gilbert Shelton.

The three are warped in their own unique way the idiot, the street smart and the nerd, but they maintain common traits such as a love for consuming copious amounts of mind altering drugs (though, they turn their noses up at heroin), chasing loose hippie chicks, as well as scoffing at the idea of working a 9 5 job