This book collects Amazing Spider-man #20-30 and Annual #2.
First of all, this Volume in Spider-man's adventures was not quite as good as the prior two particularly Volume 2. However, the quality doesn't drop much. The first two collections contained the introduction of Spider-man's most amazing foes, the Sinister Six, and the superb story arch from Amazing Spider-man #17-#19.
This book is less groundbreaking. As he did with Fantastic Four, once Lee has a good stable of established villains, he tends not to tinker too much. Issue 20 sees the introduction of the Scorpion and Issue 28 sees the introduction of Molten Man (definitely not in Spidey's pantheon of memorable villains) but the book does have some great return appearances by Green Goblin and Mysterio. Then, of course, there was the precursor to the Spider Slayers in Amazing Spider-man #25, which was an absurd looking but powerful robot with J Jonah Jameson's image on it that would later be adapted to the 1960s cartoon series.
In addition, we see some key milestone for Peter including his high school graduation and a break up with Betty Brant in Amazing Spider-man #30. Comic relief comes into play when Peter loses his costume after battling the robot in AS #25 and he spends the next two issues trying to manage with a costume store knock off that ironically saves his secret identity.
Overall, this is Spidey the way Stan Lee made him: fun, with lots of problems, and a great cast of villains. Five stars all the way.