Thank you all for your comments about ATT, Titan and Wesley. I've always been fond of Wesley and I always wanted to know what happened to him after he left with the Traveller.
Of course, I picked up the first ATT-novel back when it was released, but it just didn't work for me, and I put it down at about the halfway mark. That's also why I never read any of the other ATT-books, even though some of them come highly praised. But then, I'm not a huge fan of Titan, either (so far couldn't finish book 4), and I doubt that even the inclusion of Wesley would change that.
But then again, I think my tastes in ST-books just changed - or rather didn't develop in the same direction as the editors'. Right now, I'm trying to obtain copies of the older numbered TOS-books. I've found that I enjoy the episode-like and more or less independent adventures more than the story arcs of nowadays. On the other hand, I think I've read all the Spock books out there already... *sighs*
Also, I'd love to have seen the cover art for Metamorphosis that you described, Therin...