All in all, it's a pleasant read. The problem is that Shenkman seems to get carried away with the sound of his own voice, forgetting to fill in little things like details, attributions, etc. And sometimes, his "debunking" is unnecessary.
For example, Shenkman spares great pains to tell us that works of fiction (Shakespeare, Hans Brinker, etc.) aren't true at all - they're fiction! (Perhaps in the sequal he can inform us that Harry Potter isn't a real person).
Although he admits his biases up front, this doesn't give him carte blanche to revel in them. Shenkman is unabashedly Ameri-centric, and his prejudice against other nations is sometimes appalling. For example, he denigrates the British for not being completely stoic during the Battle of Britain in WWII. His evidence? One person's diary shows that he (gasp) went to two luncheon parties during one week! Horrors! He denigrates heroes of France, England and India because, basically, they were human. God forbid!
The book isn't all bad. Shenkman (when he actually quotes his sources and doesn't prattle on about minutia) does a great service by asking us to examine our history instead of getting it spoon-fed to us. As such, this book makes a nice starting point for the re-exploration of history. If only he'd given us more to chew on, instead of a thin, sarcastic gruel.