Just about everyone, when asked, will place Jesus at the center of Christianity. Those same people, however, base their conceptions of Christianity on what other people said about him, rather than what Jesus said himself.
Christianity, then, isn’t the religion of Jesus, it’s a religion about Jesus.
To pick a glaring example of this, Jesus never said a word about being born to a virgin. Other people hold that as a central pillar of their faith, but Jesus didn’t think it worth mentioning, if he believed it at all.
Recovering Jesus makes a positive case for who Jesus was. It examines him directly, divorced from what other people said about him. That is, it ignores all the things people have believed about Jesus, and examines the things he said and demonstrated himself.