First of all, I would also try the library while you're in search of new authors. It's an easy and affordable way to check out authors. Libraries also often have lists of authors and who readers find comparable. I know Keller's Library is under construction, so you might check out another local library (You usually don't need to be a resident of that city to enjoy privledges). Our list includes over 20 local libraries, along with contact info and links:
http://www.familyeguide.com/index5.php?id=13&sid=42
By the way, the Keller library is having a magician this afternoon at 2:30 if your son is interested. It's at the Senior Center, which I believe is where they moved many of the books during the renovation, so you can browse while you're there.
In terms of specific authors, it would be nice to know what else you've enjoyed besides Twilight, or what genre you're into. I personally like suspence, criminal drama, some light humor included, some light romance included... but not romance novels.
Authors I've enjoyed include Janet Evanovich, Sue Grafton, Lisa Scotoline, Lisa Gardner, John Grisham, James Patterson, etc.
Good luck!
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