This is my third book by Nabakov. I had heard that it really formed a set with Lolita and Pale Fire and addressed similar themes.
It does do that but not as well as the other two books. It also is about the difference between appearance and reality. Pnin at first appears to be a buffoon but he is really a noble man victimized by those around him. Like Pale Fire it is a comedy. It ramps up in the last chapter where we get the narrators direct opinion of Pnin. The whole work is incredibly well written. Nabakov for some strange reason was just one of the best constructors of an English sentence who ever lived. His prose is dazzling.
The book is really good, very readable and entertaining, but not quite the work of genius that Lolita and Pale Fire are.