The Element Encyclopedia of Witchcraft: The Complete A-Z for the Entire Magical World - Judika Illes 2005

The Three Spirit Nights
Calendar of Revelry and Sacred Days

In Welsh tradition, these are the nights when all kinds of spirits and denizens of various other realms are free to ramble and roam around Earth. If you wish to rendezvous with them or you have some practical business involving these spirits, the three spirit nights provide your maximum opportunity: May Eve; Midsummer’s Eve and Halloween.