This document discusses auction theory, types of auctions, and software agents used in auction systems. It describes common auction types like English, Dutch, blind, and Vickrey auctions. It also outlines the components of an auction system, including agents that help purchasers bid, sellers register items, and facilitate the auction. The document explains how software agents can autonomously act on behalf of users to perform tasks like monitoring auctions and suggesting bid prices. It contrasts key properties of software agents like autonomy, reactivity, and goal-driven behavior with traditional software programs.