I'd say that this order was prescribed by The Da Vinci Code (the book)'s high success. While Dan Brown might have been regarded as a best-selling author even before The Da Vinci Code, this book was a major success world-wide and gathered an attention much higher than Angels & Demons or any of his previous books did, I think. So it was just a matter of ...
It doesn't really matter.
First of all, as you have correctly noticed, the films were made in a different order than the books (not only was Angels & Demons filmed after Da Vinci Code, they also jumped over The Lost Symbol, as explained in this related question). So this on the one hand means, the books themselves don't really build extensively onto ...
There are many differences between the movie and the book:
In the book, the person who finds Robert Langdon and Sienna in the Church where Dante was baptized is a man named Jonathan Ferris, who claims to be working for the WHO but is in reality an actor working for the Consortium. In fact Ferris was the one who pretended to be Dr. Marconi, who seemingly ...
In a nutshell, the ending in the book was too drawn out and "wasn't cinematic" in terms of keeping the audience engaged.
According to an interview with director Ron Howard:
"My recollection is, Langdon wasn't really actively involved," Howard
told us. "It was so complicated and not really movie-ish. He got [to
Istanbul] and it had already been ...
Would Langdon ever let Sienna do such a thing?
In matter of life and death he would let her do because for him any piece of art is less valuable than life (also true in real life ).
Following instances support my above statement.
In Da Vinci Code Langdon throw away the Cryptex for saving Sophie Neveu's life.
In Angels and Demons he tore apart a page from ...
According to Fred Hawson:
While the basic plot is the same, the film departed from the book in
certain details. Scriptwriter David Koepp injected a romance angle
between Langdon and Dr. Elizabeth Sinskey of the World Health
Organization, which I admit was an interesting cinematic angle,
however contrived. They also significantly changed the ...