For many of us, Sapient’s “Information Architecture: Practice Definition and Process Framework” (universally known simply as “the IA Bible”) was the first time we had ever seen an exhaustive documentation of UX design methodology (except nobody was calling it “UX” quite yet). It was released in March 2000, and copies of it were coveted. I still have my copy.
Up until it came out I was swimming in techniques, and did not understand how any of it came together. I think the IA Directors understood it better, but according to this document, it was only after they gathered and combined their knowledge that anyone felt they had anything like a complete picture. I think this is a historic document, and I collect design books. If you know of a book that laid out the human-centered design process like this earlier than March 2000, please let me know.