Not my favourite of Meltzer's books. Somewhat too predictable, and the ending wasn't all that fulfilling. I enjoyed what the Book of Lies/Truth turned out to be, but there were too many loose ends with the main characters.
In general, it felt too much like another off-the-shelf secret-society-gone-wrong quest-for-an-ancient-artifact novel than a good thriller/mystery. More specifically, there was nothing about the novel that made me cheer or fall in love with it. I didn't get attached to any of the characters. I didn't get attached to this idea of the first murder weapon being a book. There was just nothing that made me care, so I went through the entire book just waiting to see what happened next.
Meltzer worked too hard to interweave his story idea with existing Superman history too. I like Superman, although I'm not an avid reader of his comics or any others. But the digressions into history did not entertain me; they left me unfulfilled. Overall, I continued reading the book just because I wanted to finish it, and not because I was invested in the characters or the plot.
Worth reading? Sure. I liked it. It turned out okay. Worth reading twice? No. And if you have other Brad Meltzer books to read, read those ones first.