This is the third in a series of monthly calendar posters created by Tom Weller to promote Country Joe and the Fish.
In 1966, Country Joe & the Fish worked regularly in Berkeley at The Jabberwock coffee house on Telegraph Avenue, and became familiar faces at the two San Francisco ballrooms, the Avalon and The Fillmore Auditorium.
They had a penchant for self-promotion and, with their manager Ed Denson printed up posters and calendars using the style of the times. Tom Weller, "artist in residence," created these images. As another example of their self-promotion, Ed, who also wrote a column for the weekly Berkeley Barb, came up with the idea to let their fans know what was happening with the band at all times; so they took out a 52 week 1/4 page ad in the Barb informing their audience where they were going to be in the coming week -- even if it was in Vancouver!
Ed Denson is actually the nickname of Eugene Denson. Since his initials were ED, they all just called him ED Denson.