Putting on my Trekspert hat I have to point out that Shatner has indeed "written" a number of Star Trek novels, particularly an alternate universe where Kirk didn't die from the events depicted in Generations. I have not read any of them. Life is short and precious...

BUT, there is also a recent novel all about Garak, written by the delightful Andy Robinson, and I believe the audiobook is performed by him in-character and honestly I'm shocked I haven't listened to it yet because Garak is The Best. youtu.be/4n8j6z8fQ_c?...

Especially the Lies

YouTube video by Nippashish