WESTLAW is an online interactive system that enables the user to carry on a dialogue with a data base stored in a computer at West Publishing Company's offices in St. Paul, Minn. Seated at a terminal and entering a search request consisting of the words, numbers, phrase, or combination thereof that describe a legal problem, the user can retrieve documents containing such terms from any State of Federal court. Any search request can be modified by the user to include or exclude additional terms. This interaction between the user and the computer gives the user great freedom in framing and modifying search requests based on prior results. The data base contains the full text and headnotes of all decisions of the United States Supreme Court, starting with 1932 and the United States Courts of Appeals and District Courts starting with 1961. Starting with 1978, the full text and headnotes of all reported decisions of all State courts are in the data base. Additionally, the data base contains the headnotes of all reported State court decisions from 1967; under the topics drugs and narcotics, civil rights, products liability, public contracts, and securities regulation, the data base contains headnotes dating back to the earliest reported cases. An important feature of the system is the West Key Number System as part of every document. A hypothetical example of how the systems used is provided and four footnotes are included.