This was the second and, sadly, last of Maggin's original Superman novels. The first was in many ways a retelling of the origin story while balancing that out with a new story and adventure. This one is, well, different.
One of the things that makes the old superheroes seem less relatable to modern audiences is their code. Superman does not kill. Period. That's who he is. Now, of course, this code wasn't in place in the very early comics, but pretty soon, the writers decided to make all their superheroes have a similar code. So Superman is the big Boy Scout. He doesn't steal, he doesn't lie (with the exception of protecting his secret identity), drink, smoke or any of those things, because that's the whole point. It's not his powers that make him Superman, it's his code and his ideals and his reasons for doing what he does.
In 'Miracle Monday', a demon from Hell comes to test the Man of Steel. Not to beat him up or kill him; merely to make his life unbearable until he violates the very code he stands for. That's the whole point to this story. As such, it becomes very harrowing, indeed. For instance, the demon sets off EVERY nuclear weapon on the plant simultaneously - even the secret ones, even the hidden ones, ALL OF THEM. And of course, this is a job for Superman. As before, Maggin doesn't downplay the hero's great powers. Rather, he writes stories that challenge those powers to their breaking point. This book is very different than 'Last Son of Krypton': the first is sci-fi more than anything, while this is more about magic and myth. But the characters at the heart of the story stand out and make it seem immediate. Not to give anything away, but major events happen in this story to the accepted Superman dynamic, and it is fascinating to see how the different characters response when secrets are brought out. Again, one of t hose books that defined a character for me and made me a lifetime Superfan.