Yeah, 'The Fallen' is part of his Amos Decker series. Decker's the guy with that hyperthymesia and synesthesia from the football injury, so every book is him using that perfect memory and weird sensory associations to solve stuff. This one's the fourth, I think, after 'Memory Man', 'The Last Mile', and 'The Fix'.
You can read it on its own since Baldacci does a decent job re-introducing the core concept, but you'd miss a lot of the emotional buildup with Decker and his FBI partner, Alex Jamison. Their partnership develops across the books, and you see Decker grapple with the fallout from his family's murder more in the earlier entries. The series is pretty consistent in tone—dark, procedural, with that central gimmick. If you liked one, you'll probably like the others.