Asprin's MYTH series was a wild best-seller in the eighties. It's light fantasy, heavy on the puns. His 'Phule' series was also well-received (humorous SF) and he co-edited the very successful 'Thieves World' series with Lynn Abbey, his former spouse.
The MYTH books started off with a good head of steam. The premise and setting (apprentice magician paired with grouchy cursed mentor/dimension hopping fantasy adventures) were original enough to provide a mine of situations for Skeeve and Aahz to claw through. As the series progressed, however, the quality declined along a swift arc mirroring the quality of life for Asprin and his characters. Happy-go-lucky Skeeve, the apprentice, became a victim of his own success and an incipient alcoholic. Asprin, meanwhile, got divorced, got writer's block, and got into a huge mess with the IRS over, allegedly, unreported income. He wrote almost nothing for almost ten years. Concurrently his publishing company declared bankruptcy, and the MYTH books went out of print.
Meisha Merlin, a small press, bought the rights to the original MYTH series and is reissuing them. Asprin is apparently back in the saddle and has, according to the introduction to MYTH-ion Improbable, 'resolved' his IRS problems. MYTH-ion Improbable, published 2001, was his first contribution to the MYTH canon since Sweet MYTH-tery of Life in 1993.
Also in the introduction he explains that he was having difficulty resolving the threads created in the last installment, and a friend suggested he write a 'fill-in' novel set between two earlier books. Hence Improbable is a self-contained adventure set before Skeeve became a wildly successful interdimensional traveler and started hitting the bottle.
It really shows that Asprin has been off his feed. The writing is stilted and the characters lack much of their original charm. Skeeve and Aahz aren't particularly nuanced characters, but Tanda, their green, buxom partner in crime, was delicately balanced between ditz and manipulator. In Improbable she's entirely wasted.
This was not a good book. It will be of interest to completists, but not really to anyone else.
I'm more interested to read Something MYTH Inc. It's been ten years since Asprin left a lot of balls in the air, and I want to see where they land.