As part of the study of human information search strategy, the concept of the search tactic, or move made to further a search, is introduced. Twenty-nine tactics are named, defined, and discussed in four categories: monitoring, file structure, search formulation, and term. Implications of the search tactics for research in search strategy are considered. The search tactics are intended to be practically useful in information searching. This approach to searching is designed to be general, yet nontrivial; it is applicable to both bibliographic and reference searches and in both manual and on-line systems.