Apparently, Bowie knew he was dying as he made his final album (just released on January 8, two days before his death) and intended it to be a goodbye. Not sure how many musical artists had a chance to do this and/or actually did it. Only George Harrison's Brainwashed comes to mind.
I would highly recommended Blackstar to anyone who appreciates good music. Just hours before learning of his death, I was on the phone with friends imploring them to buy this album, which I think is really great. So Bowie in that it is so different and unusual. As an old advertising campaign said, "There's New Wave. There's Old Wave. And there's David Bowie." Or something like that.