I was perusing online bookstores in my never ending hunt for mash-ups, etc. when I came across a series of books that caught my eye: The Girl's Guide to Everything Unexplained. This is a series for Grade 3 - 9 (ages 8 - 14) written by Jen Jones. They will be published in early January 2011 by Capstone Press.

The series description:
Mythical creatures are hotter than ever, but much of what’s out there is inappropriate for young girls. This age-appropriate series has everything girls want to know about popular unexplained phenomena, including: origins, key characteristics, special powers, and much more! Quizzes, creature profiles, and yearbook awards round out these high-interest books.
Here are the covers:

What I Found - The Girl's Guide to Everything Unexplained - November 15, 2010

What I Found - The Girl's Guide to Everything Unexplained - November 15, 2010

What I Found - The Girl's Guide to Everything Unexplained - November 15, 2010

What I Found - The Girl's Guide to Everything Unexplained - November 15, 2010

The back cover copy for the books:

Is your crush a vampire? Do you know how to stop an attacking werewolf in its tracks? Can you tell the difference between a zombie and your math teacher? Fun features like quizzes, creature profiles, and yearbook awards will help you learn everything you need to know about these mythical creatures.
Here's a peek at the inside of The Girl's Guide to Vampires: Everything Enchanting About These Immortal Creatures.
What I Found - The Girl's Guide to Everything Unexplained - November 15, 2010

These are just the sort of books I would have loved when I was growing up. I hope to take a more in depth look at the books when they are published next year.