Chris Voss's Never Split the Difference is the most-read negotiation book of the last decade. It deserves the readers it has. It is also one school out of three, and the reader who stops there carries a single toolkit through a field that asks for more.
The first follow-up is Getting to Yes by Roger Fisher, William Ury, and Bruce Patton — the founding text of the Harvard Negotiation Project and the standard introduction to the field. Read it for the four principles: separate the people from the problem, focus on interests rather than positions, invent options for mutual gain, and use objective criteria. Read it especially for the chapter on what Fisher calls negotiation jiu-jitsu — what to do when the other side will not engage with the principled framework. The book is shorter than Voss's, drier, and structurally clearer. Where Voss tells stories, Fisher and Ury build a method.
The second is Negotiation Genius by Deepak Malhotra and Max Bazerman — the cognitive-bias school, thirty years of experimental research at Harvard Business School on what negotiators actually do as opposed to what they think they do. Read it for the chapters on anchoring, framing, and the winner's curse. Where Voss teaches you to manage the other side's emotions and Fisher teaches you to manage the structure, Bazerman and Malhotra teach you to manage your own reasoning. The slowest read of the three. Also the one that produces the most catch-yourself-in-the-act moments.
The third is 3-D Negotiation by David Lax and James Sebenius — the move-after-Fisher book for readers who want to go further. Lax and Sebenius argue that most negotiation literature focuses on the conversation in the room, and that the more important work is structural, done before the conversation begins. Who is at the table? Who should be at the table but isn't? What is the scope of the deal, and could it be reshaped? Their three dimensions — tactics, deal design, and setup — give you a vocabulary for the part of negotiation that happens outside the meeting. For anyone whose work involves multiple stakeholders or complex deal structures, this is the book that turns reactive negotiating into proactive deal-design.
A fourth, slightly off-list option, worth mentioning: Stuart Diamond's Getting More, the Wharton perception-first school. Diamond's central insight — that nine-tenths of a negotiation lives in the other side's mental model, and your move is to read that model and adjust there — is the third leg that Voss and Fisher don't quite cover. If you found Voss interesting but slightly cold, Diamond is the warmer cousin in the same family.
The honest order: Fisher and Ury first, to give Voss a structural counterpart. Bazerman and Malhotra second, to give both a cognitive grounding. Lax and Sebenius third, to expand the frame beyond the conversation in the room. Diamond as bonus, if the reading is going somewhere personal.
Four books, four schools, one field. Voss is the entry point most readers stumbled into. The rest of the field is what makes the entry point pay off.