Term indexing supports the construction of efficient automated reasoning systems, as e.g. automated theorem provers, by allowing rapid access to first order predicate calculus terms with specific properties. This monograph provides a comprehensive, well-written survey on term indexing in general and presents new indexing techniques for the retrieval and maintenance of data that help to overcome program degradation in automated reasoning systems. Theoretical foundations and applicational aspects are treated in detail; finally the PURR prover for parallel unit resulting resolution is discussed to demonstrate the importance of careful implementations.