Yesterday Samir Mathur gave a colloquium here on the black hole information paradox. I've known Samir for many years; he was an assistant professor at MIT when I was a postdoc up the river. I've always found him to be a very precise and clear thinker.
On his web page there is a very simple introduction to the paradox. The initial presentation emphasizes the role of negative binding energy in black hole physics, which is related to the question of monsters: configurations in classical general relativity with more entropy than black holes of the same mass. (Slides.)
Here is a recent paper in which Samir discusses the black hole firewall problem and subadditivity of entropy.
Samir in action giving a more technical seminar earlier today:
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