The GCVS is the only reference source on all known variable stars. This version contains all of the electronically-readable version as distributed by the Sternberg Astronomical Institute and Institute of Astronomy (Russian Acad.Sci.), Moscow. It includes the catalog of variable stars, updated and completed with the Name-Lists of Variables Stars Nos.67-77 (see IBVS No.2681,1985; No.3058,1987; No.3323,1989; No.3530,1990; No.3840,1993; No.4140,1995; No.4471,1997; No.4659, 1999; No.4870, 2000; No.5135, 2001; No.5422, 2003) a catalog of suspected variables, a cross-index of variable star names, a catalog of extragalactic variables, and a catalog of supernovae. Introduction: The present improved electronic version of the GCVS4 Volumes I-V, combined with Name-Lists of Variable Stars Nos.67-77 and NSV catalogue is also available from Sternberg Institute via anonymous ftp, where they are stored as zip and text files at ftp://ftp.sai.msu.su/pub/groups/cluster/gcvs/gcvs gcvs_cat.dat is the combined computer-readable version of the GCVS4.2 Vols. I-III (Kholopov et al. 1985-1988) and Name-Lists of Variable Stars Nos.67-77 (1985IBVS.2681....1K, 1987IBVS.3058....1K, 1989IBVS.3323....1K, 1990IBVS.3530....1K, 1993IBVS.3840....1K, 1995IBVS.4140....1K, 1997IBVS.4471....1K, 1999IBVS.4659....1K, 2000IBVS.4870....1K, 2001IBVS.5135....1K, and 2003IBVS.5422....1K) published in the system introduced during the preparation of the 4th GCVS edition; the stars are arranged in the order of their names inside constellations. The total number of designated variable stars has now reached 38624. Errors detected in the printed Volumes I-III and in the Name-Lists were corrected; the file includes also improved positional information, light elements, classifications etc. crossid.dat corresponds to Vol. IV of the GCVS4, and contains all variables, including extragalactic variables, stars from the Name-Lists, and stars suspected of variability since the compilation of the NSV catalog and its supplement. The authors tried to provide as complete lists as possible for the stars identified with the catalogues HD, BD, CoD, CPD, BS, ADS and for the stars with preliminary HV (Harvard Variable) designations; a list of the catalogues mentioned is included in the file "abbrev.txt". The final, Volume V (extragalactic variable stars) consists of two catalogues. The catalogue of variable stars in external galaxies contains 10979 variable stars in 35 stellar systems (including the Magellanic Clouds, the large galaxies in Andromeda and Triangulum, etc., see evs*.dat). The catalogue of extragalactic supernovae includes 984 confirmed or suspected supernovae (see sn*.dat) The file nsv_cat.dat is the merging of a compilation of 14811+11206 stars suspected of variability (II/140) and its supplement (II/219). It is the successor to the "Catalogues of Stars Suspected of Variability" published in 1951 and 1965 by Kukarkin et al. Data contained in the present catalog include positions, magnitudes, variability types, alternate designations, and references to the literature.