Being a Beatles fan from the 5th grade on into adulthood, there's a lot of stuff I already know, but there are details and explanations that really reveal the characters behind the public image in ways that are sometimes surprising, and often disappointing.
Alfred Molina does a nice job with the narration.
At the same time, I agree with you about getting lost in good fiction. I've been on a bit of a middle-ages fiction jag recently. Within the last month, I've read 2 of the Brother Cadfael mysteries (crusader-turned-monk, herborist, and medieval CSI; set in England in the 1100's -- written by Ellis Peters) and 2 of the Sister Fidelma mysteries (a lawyer/advocate/investigator, member of a religious order and sister to the kings; set in Ireland in the 600's -- written by Peter Tremayne). Both series are loaded with accurate (and fascinating) church, social, and legal history.
Next, I want to get Umberto Eco's "Name of the Rose" (Also set in the middle ages. I wonder what's up with that?). Recently, I had a chance to sit down with a copy at a local bookstore; the introduction alone is far better than the movie with Sean Connery and Christian Slater!