Even though I file it in the same drawer with Wikipedia (probably not the most reliable source, but quite entertaining and a fantastic jumping-off point for further research on topics), I'm a big fan of Michael Farquhar's “A Treasury of Royal Scandals: The Shocking True Stories History's Wickedest, Weirdest, Most Wanton Kings, Queens, Tsars, Popes, and Emperors”. He's got a few others, but this one has been my favorite. I'm also headed to the bookstore today to hopefully pick up a couple of historical atlases. I spotted some the last time I was there, and I'm almost certain that one of them was specific to Celtic history. Clearly a sign, right?