Fantasy with Skyships made from dragons and a main character thief named Bjorn(?). Read before 2002.

[Blake]

I read this book over 20 years ago and it just popped back into my head and I would love to reread it. I think the thief is a shapeshifter who turns into a bear but worries that he will lose his way back to humanity if he stays a bear for too long.

[Joseph]

The Shattered World by Michael Reaves! One of my favorites, and kind of sadly obscure at this point. Although someone did just get a license to publish an RPG setting based on the world.

[Lobstergirl, au gratin]

Blake, was that your book?

[Justanotherbiblophile]

Joseph wrote: "The Shattered World by Michael Reaves!

There's a second book in the series: The Burning Realm

[Joseph]

Yep! Sadly, although it ends on a cliffhanger, and I think at one point the author was working on one, I don't think we'll ever get a third at this point.

[Justanotherbiblophile]

Joseph wrote: "I don't think we'll ever get a third at this point."

Sadly, you are correct:

"Reaves has Parkinson's disease, and for a time maintained a blog concerning his experiences dealing with the disease and its effects. Typing is now difficult for him, and by his own account, he has lost the ability to speak coherently."