This catalog contains data for 1020 cataclysmic variables (CVs). It includes coordinates measured in the reference frame of the Hubble Space Telescope Guide Star Survey for non-novae and from the literature for novae. Also given are the variability type, the magnitude range, references to finding charts and spectroscopy, the galactic latitude and longitude, and the year of outburst for novae. The second edition includes plate identification information for the coordinate measurements, a reference to the classification, proper motion information where appropriate and a table showing the CVs observed by space-based observatories. This version of the catalog includes 195 new objects (172 CVs and 23 non-CVs), revised identifications for 57 objects, and revised classifications and spectral references where available. Introduction: A Catalog and Atlas of Cataclysmic Variables - Second Edition as presented here contains a list of all cataclysmic variables discovered prior to May 1996, as derived from the literature; there are a total of 865 cataclysmic variables (276 novae, 372 dwarf novae, 162 novalike variables, 47 objects classified only as cataclysmic variables, 6 interacting binary white dwarf (IBWD), and 2 possible supernovae/novae) and 155 object formerly classified as cataclysmic variables. A Catalog and Atlas of Cataclysmic Variables - Second Edition as distributed here is in two files. The first file contains the cataclysmic variables in constellation order, while the second contains the objects in order of increasing right ascension. The tables below give the characteristics of these files. A copy of the document catvar.tex should be transmitted with any additional copy of this catalog.