Given that the book is in Spanish, you can understand the president's surprised look. Obama couldn't tell what it was or what the hell the book was about. I doubt Chavez's broken English helped in the short explanation. Chavez should have thought to have given President Obama an English translated version, given that they do exist.
Chavez definitely attempted to ambush Obama for a photo op, the sneaky fat bastard.
As Obama later stated, he thought Chavez was giving him one of
his(Chavez's) books, and Obama was thinking he'd return the favor later by giving him "The Audacity of Hope" or "Dreams From My Father."