Fantastic Four (1961 series) #25

We find out that the Hulk can read. Plus, this is the infamous story where Stan Lee accidentally called his hero's alter-ego "Bob Banner" leading to Bruce's official naming as "Robert Bruce Banner." ~ Peter Silvestro

This 2-issue story is the Avengers first real foray out of their own comic (not counting the brief individual cameos in Tales of Suspense #49), following on from Avengers #4. In publication date order this honour should really fall to Journey into Mystery #101, but the Official Indexes move that story back to after Avengers #6. The story continues Avengers attempts to control the Hulk which dominate their first 5 issues. The Hulk was last seen in Avengers #3 as Bruce Banner slipping away from his partnership with Sub-Mariner against his former teammates the Avengers. The Avengers, now with their new member the revived Captain America are still trying to capture him. Hulk and Banner are now swapping identities more frequently and seemingly at random. And Hulk claims to be getting more powerful a nd more in control each time. Hulk's pal Rick Jones leads Avengers to Banner's secret cave laboratory. But Hulk has already been there ans smashed all the machinery, including the gamma ray device with which Banner and Hulk could transform at will with Rick's help. At the end of Avengers #4 Rick was worried how Hulk would feel when he learned he had been replaced by Cap. His worries come true here (despite the fact that Hulk actually quit the Avengers (in Avengers #2)), but Hulk also feels Rick has betrayed him by staying with Avengers. Hulk met the FF back in #12, during the run of his original series. Back then it was suggested that Mr Fantastic had worked out the relationship between Hulk, Banner and Rick. But there is no suggestion this issue or next that this is true.