This book is Dan Brown's first novel, and deals with moral issues such as the debate between science and religion. It outlines many of the internal workings of the Vatican (some in great detail) as a plot to blow up the Vatican unfolds during the conclave.
"Angels and Demons" has many similarities with Brown's other books -- all events happen within 24 hours, it starts with a murder, and then takes a breakneck pace through many European settings. In this book, much of the artwork is by the noted sculptor Gian Lorenzo Bernini.
Just as with Brown's other novels, there is a mixture of fact and fiction that some readers find entertaining, but others find inaccurate and misleading, to the point of promoting conspiracy theories.
The book was originally published in 2000, to no particular acclaim, with a first printing of less than 10,000 copies. In 2003 though, it was re-released because of the attention around the second Langdon book (Brown's fourth novel), "The Da Vinci Code", which as of 2005 has sold over 60 million copies.
Angels and Demons did considerably better than Brown's other two books, Deception Point and Digital Fortress, because of its connection with The Da Vinci Code, and made it into the New York Times Bestseller List (in 2004, all four of Brown's novels were once on the list in the same week). As of 2005, there are now over 8 million copies of "Angels and Demons" in print, in a variety of languages.
The book's popularity has led to a corresponding increase in tourism to the book's locations in Rome.