When he first read the script for Batman, he planned on refusing it, since he's never been a fan of the Batman adventures. As a child, he didn't read the comics and only seen a few episodes of the campy Adam WestTV show, but he became really engrossed with what the film was trying to do, and finally accepted.
When it was announced that Keaton was going to play the title character in Batman, Warner Bros. office was flooded with countless letters from comic-book fans, insisting that Keaton was the worst possible choice for the role. Batman creator Bob Kane was especially exasperated. Looking back, Keaton is now considered one of the best Batman, and other actors are personally measured by his example. Keaton remarks: "I am Batman. I'm very secure in that".