Several versions of WAIS databases were examined to determine how Boolean searches are implemented. The versions tested were: CNIDR's freeWAIS, versions 0.03, 0.04, and 0.05 Ulrich Pfeifer's (Univ of Dortmund) freeWAIS-sf, version 1.1 WAIS, Inc.'s versions 1-0-11 and 2.0.0