How the infamous ELIZA chatbot transformed ideas about AI and society's response to them. As we reach the 60th anniversary of ELIZA's public debut, Inventing ELIZA offers the first comprehensive critical analysis of Joseph Weizenbaum's groundbreaking chatbot system through the lens of critical code studies. Drawing upon extensive archival research at MIT, Stanford, and UCLA, this book presents the rediscovered original source code of ELIZA alongside previously unseen scripts (missing for decades), revealing a far more sophisticated system than previously documented. Sarah Ciston, David Berry, Anthony Hay, Mark Marino, Peter Millican, Arthur Schwarz, Jeff Shrager, and Peggy Weil trace ELIZA's development (1965-1968), reveals that Weizenbaum created a chatbot within a conversational programming environment with previously unknown innovations well ahead of its time. Through close reading of both code and paratexts, the book reconstructs ELIZA's conceptual evolution and situates it within the historical context of early AI development. Book website: https: //findingeliza.org and elizagen.org. The website includes a faithful recreation of the first Chatbot and news about continued research.