I think I first saw Ronald's Searle's work on the cover of Fear and Loathing in Las Vegas by Hunter Thompson. I just love this world-weary cat! Searle's drink of choice was champagne, apparently even while working (or maybe especially while working?), but even so, an amazingly prolific artist. He has a gorgeous facility with ink lines - some thick and jittery, others delicate and graceful, combined with those expressive spatters. I also appreciate his subtle use of color. He often colored only a single object in an otherwise black and white image.
Here's the original Searle, below. I didn't fully capture his frenetic, jiggity-jaggedy lines, but attempting to was an education.