The book is existentialist, and its main joke, according to Gerber, is that there is no joke: "that life's most serious moments and most incredibly dumb moments are often distinguishable only by a momentary point of view."

Howard the Duck - Wikipedia, the free encyclopedia

Update:

itsjanna said: "Brunner left the series because he considered Howard a cartoon in the real world, whereas for Gerber, Howard was a flesh and blood duck." Oh man, what an amazing disagreement.