If you loved the offbeat, clever wordplay and dry, self-aware humor that Fred Cassidy brings to his cosmic misadventures, you’ll delight in The Hitchhiker's Guide to the Galaxy. Arthur Dent’s journey through the absurdities of space is packed with snappy dialogue, comedic timing, and satirical takes on the universe that will feel right at home after Zelazny.

If you were hooked by the way Doorways in the Sand keeps you guessing with shifting realities and surprise reveals—like the true nature of the Rhennius machine or the sudden plot pivots—you’ll enjoy The Man in the High Castle. Dick’s alternate-history thriller is full of reality-bending moments and plot twists that challenge your perceptions at every turn.

If Fred Cassidy’s laid-back attitude, knack for getting into trouble, and ambiguous ethics made him an endearing guide through intergalactic intrigue, you’ll find a kindred spirit in Slippery Jim diGriz. The Stainless Steel Rat features a witty, lovable rogue who bends the rules, outsmarts his pursuers, and charms his way out of every scrape.

If you enjoyed the way Doorways in the Sand plays with perception, identity, and reality—making you question what’s actually happening—A Scanner Darkly will resonate. Bob Arctor’s shifting sense of self and the hallucinatory, reality-blurring narrative deliver a trippy, intellectually playful ride akin to Zelazny’s style.

If you found yourself reflecting on the metaphysical puzzles and existential musings sprinkled throughout Fred Cassidy’s journey, Stranger in a Strange Land will strike a chord. Heinlein’s tale of Valentine Michael Smith’s outsider experience on Earth is filled with philosophical debates, questions of identity, and provocative ideas about what it means to be human.