2 Valeria De Paiva and Vaughan Pratt

This special volume of Theory and Applications of Categories (TAC) addresses the theme “Chu Spaces: Theory and Applications.” The idea for the volume grew out of the workshop of that name organized by the volume’s editors in association with the conference Logic in Computer Science (LiCS’2000) held at Santa Barbara in 2000. We conceived the scope of the volume as not being limited to the material presented at the workshop itself but extending beyond it to embrace a wider range of topics related to Chu spaces and Dialectica constructions. By way of complement to Barr’s article in this issue on the conceptual evolution of Chu spaces we offer here some prefatory remarks of our own on the nature, uses, and history of Chu spaces. We then give our perspective on where this volume’s papers fit in the overall scheme of things. Further material on Chu spaces can be found at the website http://chu.stanford.edu maintained by the second editor.