I have just discovered this character and really like him. I have been out of the loop with comics as of late, but The Sentry volume one was fantastic! I love the way they make him the first and most powerful superhero that has had an influence on all the major marvel characters. His disappearance and the way no one remembers him was done very well. I also love the way his dark side is the manifestation of his greatest enemy the Void.
Anyway, where does the story continue after volume one? At the end he had to erase his memory from the world again. I see he is in the New Avengers and Sentry volume two but how does everyone remember him again?
Spoilers follow
[spoiler]
Well, in New Avengers no one knows who he is. The New Avengers started with Matt Murdock and Foggy going to see the Sentry in a super-prison, at the request of Mr. Fantastic. The Sentry asked to be imprisoned because he believed he had killed his wife. A break-out attempt occurs during this visit, and the Sentry intervenes to help stop the super-criminals. They confront him later with his wife, still alive, and he freaks out and reverts to his civilian identity, apparently blocking out what had happened. The combined forces of Shield, the New Avengers, X-men, Fantastic Four and Inhumans show up at his house. The Sentry has a panic attack that the Void will show up because they know about him, and the Void indeed does, and proceeds to attack the assembled heroes. Emma Frost goes into Bob's mind psychically, to try to figure out what's going on and it turns out that the Void isn't a product of people's knowledge of the Sentry, he is the Sentry, or at least the manifestation of his dark side. Bob is a schizophrenic, and the Void is the manifestation of his mental illness. The whole - everyone needs to forget him bit - is revealed to have been the work of Sentry's villain the General, and the old X-men foe Mastermind, who used mental illusions to convince the Sentry that he needed to make everyone forget him in order to beat the Void.
In volume 2, it waffles back and forth that the Sentry personality and power-set is actually the creation, and that Bob is really the Void. It's also revealed the Bob drank the serum that gave him his powers trying to get stoned, and that the serum was an attempt to create another, better super-soldier. The Sentry eventually defeats the Void and throws him into the sun, but knows its only a temporary respite, since he is the Void after all, and will just recreate him.
[/spoiler]