I've been to Disney World at least ten times, but can't seem to understand the crowds. What book gives you the best info on when to arrive at the parks? Is it the "Unofficial Guide"?
Yes, I prefer the Unofficial Guide to Walt Disney World. They are runned by people just like you and me who love Walt Disney World and want to help other people to get the most out of their trips. They spend numerous hours and days for research in the parks and the whole resort, from the crowds and wait times to dining options and answers. I would trust them, they are one of the greatest resources to check out if you want to know about the crowds or anything about your next trip to Walt Disney World.
Check out their site too: http://www.touringplans.com/tp2/UG2_index.php?PageID=0
And if you buy their book, you get unlimited use of their very usefull crowd calender. It's a graph that shows which days or months that are crowded or not, and which park to go to that's less crowded, and other great information.
Check out their crowd calender as well: http://www.touringplans.com/tp2/UG2_index.php?PageID=14