Merlin trilogy

I've always been fascinated with the stories of King Arthur. I got this book a few months ago and have been slowly working my way through it. I read all of the books several years ago and wanted to read them again.  I couldn't find it now at the library, or in any other format. This one came from Amazon, I believe. I remember that I was disappointed in the 4th one, so I'm not sure if I'll reread that one. 
 I just wish this book had larger print. It's a strain on my eyes! I have to be sure to read during the daytime.