I started with Mister B Gone which is a good place to start. It’s sort of an oddball coming of age story about a demon. The Hellbound Heart is probably where I would recommend starting, though. It’s the novella that Hellraiser is based on. After that read The Scarlet Gospels, which is probably the most insane book I’ve ever read, and sort of a sequel to The Hellbound Heart. Barker wanted to put Hellraiser to bed for good, and The Scarlet Gospels certainly does that.

Sacrament is also a good starting point for people because it’s less disturbing than most. Coldheart Canyon is a ton of fun, but also possibly his goriest book. It’s also extremely readable and easy to get into.