The Dark Ages - Isaac Asimov This book definitely helped establish me on the course my life took. Reading about the "Dark Ages," I discovered that there was a fascinating world between the Romans and the Renaissance.

Of course, it oversimplified the era and it's hopelessly outdated considering the research that has been done in the last 35+ years but it gets the basic facts right, and it's a good introduction for a young reader who might otherwise be turned off by history because of the inane textbooks they're (sic) not reading in school. As usual, Asimov writes in a clear, crisp fashion that doesn't patronize the reader, and he makes things sound "exciting."