I loved The Shadow of the Wind, and I thought The Angel's Game was interesting but it didn't quite go as I expected so I'm not entirely sure how I felt about the conclusion. In comparison, The Prisoner of Heaven is a very simple story. Some of it is just as engaging and magical as The Shadow of the Wind, and I think it helped explain aspects of The Angel's Game that would make it more enjoyable as a re-read, but I also think this is the weakest of the three novels in this series so far.
This novel explores more of Fermin's background since he is about to get married but worries about the fact that technically, he doesn't exist. Fermin had to choose a new identity as a result of political issues and civil war, but what Daniel Sempere, the narrator, did not know is that Fermin has actually been declared dead in his second identity as well. After some buildup, Fermin reveals his story to Daniel, and his time in an infamous prison. David Martin, the narrator of The Angel's Game, is a fellow inmate, and this reveals a bit more about The Angel's Game, how it came to be written and Martin's mental state. There is also a bit that is either a cute homage to Alexander Dumas and The Count of Monte Cristo or a blatant rip off.
This was the fun part of the novel as it provided background, intrigue and adventure. Unfortunately, I didn't enjoy the parts that took place in the novel's present day, or the 1950s. I don't really enjoy the character that Daniel has become and this novel sets him up for a dark turn based on newly acquired information. I liked the kid that wanted answers and wanted to solve mysteries. I'm not sure how I feel about the guy that is suspicious of his wife, withholds information from her, and may be on a quest for vengeance.
As a result, I'm very curious to see what the fourth and final volume of this brings because that will be the determining factor in whether I think this was a great series, or whether I recommend The Shadow of the Wind as a brilliant stand alone novel. Technically, the books can be read out of order (at least that's part of the marketing campaign), and I certainly think reading The Angel's Game after this would provide a different and new perspective. I can't decide how I feel about reading The Prisoner of Heaven before The Shadow of the Wind, though. After all, it follows many of the same characters but a few years later, so to me, it seems more like a regular sequel; however, maybe I would feel less disappointed in Daniel the man if I hadn't met Daniel the boy first.