The electronic distribution of large astronomical databases has increased at an explosive pace during the last decade. This distribution has occurred via a combination of online access systems, magnetic tape distribution, and optical disk distribution. Examples of these methods, and the advantages of each, will be presented. Emphasis will be on CD-ROM as a distribution and archival medium and on the lessons learned with the Einstein CD-ROM Archive. CD-ROM has cost/performance advantages that are presently unmatched by other distribution and archival media. Some interesting trends in CD-ROM technology development are briefly mentioned.