Magic Time by Marc Scott Zicree & Barbara Hambly
Magic Time is the first book of a fantasy trilogy helmed by Marc Scott Zicree. This book is co-written with Barbara Hambly. Each of the subsequent books in the series is written with a different writer. Magic Time was published in 2001, and it is not aging well.
I had a difficult time getting through Magic Time. It narrowly missed achieving Did Not Finish status.