This set of papers offers insights into some of the major developments in the field of classification and knowledge organization, and highlights many of the fundamental changes in views and theories which have taken place during the last 40 years. This document begins with a series of reminiscences from former delegates of the first International Study Conference on Classification Research which took place in Dorking, United Kingdom in 1957, and continues with a collection of 15 papers by classification specialists: "The Need for a Faceted Classification as the Basis of all Methods of Information Retrieval"; "Classification in Information Retrieval: The Twenty Years Following Dorking" (E. J. Coates); "Structure and Function in Retrieval Languages" (B. C. Vickery); "Knowledge Representation: A Brief Review" (B. C. Vickery); "Natural Language Processing for Information Retrieval" (David D. Lewis and Karen Jones Sparck); "The Testing of Index Language Devices" (Cyril W. Cleverdon and J. Mills); "Indexing and Retrieval Performance: The Logical Evidence" (Dagobert Soergel); "Reflections on TREC" (Karen Sparck Jones); "On Information Science" (Carl Keren); "Brief Communication: A Note About Information Science Research" (Gerard Salton); "Unanswered Questions in the Design of Controlled Vocabularies" (Elaine Svenonius); "Needs for Research in Indexing" (Jessica L. Milstead); "Intelligent Text Processing, and Intelligence Tradecraft" (Michael L. Weiner and Elizabeth D. Liddy); "Advanced Searching: Tricks of the Trade" (Peggy Zorn, Mary Emanoil, Lucy Marshall, and Mary Panek); and "What do People Want from Information Retrieval?" (W. Bruce Croft). (SWC)