From 1978: THE INCREDIBLE HULK prose novel STALKER FROM THE STARS by Len Wein, Marv Wolfman and Joseph Silva. Published in the States by Pocket Books.
I picked this up recently and (typically) I've not had a chance to read it yet. But it looked too much fun to pass up on.
The timing hits the peak of the TV show's success but a swift bit of Googling reveals this is actually one of a series of eleven Marvel Superheroes novels, all apparently published during 1978-79.
The Green Goliath appeared solo in two of the thirteen and teamed up with Spider-man in a third. He was also one-fourth of an anthology edition with four shorter stories (also starring Daredevil, the Avengers and the X-Men).
The Web Slinger also starred in two books (and shared that billing with the Hulk on a third). Other volumes featured The Avengers, Doctor Strange (star of a TVM around this time), Captain America (ditto. Times two), the Fantastic Four and Iron Man.