Conversation so far:
What is Vortex and Ed the Happy Clown?
Brown began to weave together some of the earlier unrelated strips into an ongoing surreal black comedy called Ed the Happy Clown. Vortex is a comic book publisher
When did Ed the Happy Clown start?
Brown first serialized it in his comic book Yummy Fur, and the first, incomplete collected edition in 1989
When did Ed the Happy Clown end?
He brought Ed to an abrupt end in Yummy Fur #18 to turn to autobiography.
Did Brown collaborate with anyone on the comics?
In 1989 the first Ed collection appeared, collecting the Ed stories from the first twelve issues of Yummy Fur with an introduction by American Splendor writer Harvey Pekar.

Question: Did he work with anyone else?
Self-contained rewrite: Did Chester Brown work with anyone else?