Not all encyclopedias were published. Many were planned but not finished, quite a few were advertised but never finished or published, and some were completed but still never published. Publication was neither a given, nor a process so simple that an ambitious author could necessarily undertake it alone. In fact, behind the great majority of published encyclopedias, usually inconspicuous, was a professional publisher. The publisher could be the person who initiated the encyclopedia, or even occasionally someone who edited or wrote for it, but most publishers played a minor if any role in these activities, concentrating instead on producing the encyclopedia and putting it on the market.