I look forward to each summer like I'm a kid waiting for school to be out. Not because I actually get a kids-length summer vacation, but because many authors release new books in some of my favorite series. These series are at the top of the list because their lead characters have become my imaginary friends. I have quite a few imaginary friends and, like my real friends, they are diverse, complex, intuitive, flawed, brave, intelligent and funny. Each summer affords me the opportunity to visit them again and see where their next adventures will take them.