Sir Crassmore had as unfortunate talent for getting himself into the center of any trouble that might come along. If it couldn't be found in the Beyonds, he'd find it in the Singularity - and there it was big trouble, indeed.
Used availability for Brian Daley's A Tapestry of Magics
May 2015 : USA Paperback
January 1983 : USA Mass Market Paperback
February 2012 : USA, Canada, UK Kindle edition