How truthful is this film... no one will ever know.
How can anyone know anything about a company (CIA) that (supposedly) deals with lies... again, no one will ever know.
Important issues are presented here: imperialism, espionage, loyalty, betrayal...
This film was certainly worth watching, for Matt Damon's performance (as Edward Wilson) especially. He and *he alone* carries the film on his shoulders.
A surprise: De Niro shows a better talent as a director than an actor.
Angelina Jolie, as Wilson's wife, overacts way too much and her character is not credible because not well developed. Tammy Blanchard (who plays Laura) definitely has more talent than Jolie.
The melodramatic dialogue didn't help the movie, however well directed it may have been.
Recommendation to watch _The Good Shepherd_: Pay attention to the dates, as it is rather easy to get lost in the second act, where Russian spies and the Bay of Pigs invasion are mentioned.
Better editing and script-writing would have made the film shorter (close to 3 hours!), as many of those details were not needed to understand what was going on.
Certainly worth watching, but be prepared to endure three hours of film.