If I were to choose to read only one book from Dan Brown,
The Da Vinci Code would be the choice.
Angels and Demons is a prequel, introducing us to Langdon, the star of
Da Vinci Code. The reader does learn background information about him that is not presented in The Da Vinci Code.
It is not a bad book, just seemed very drawn out to me. The mystery surrounding the Illuminati is well developed except the resolution at the end of the book seemed a bit too tidy. The version I read, is 710 pages, which to me the story could have been shorter.
This being said, I will be looking to read the next installment,
The Lost Symbol due out this fall.