I found it interesting that this book was actually written by, in addition to a grown-up and married guy, two high school students. I guess it never occurred to me that a teenager that young could actually get a published book. Perhaps it gives me hope for my own novel --- if I ever end up finishing it.
Anyway, that's off topic. Let me start the review.
This book mainly consists of information about the different Greek/Roman gods/goddesses and the different creatures of Greek and Roman mythology. All that information was interesting, but, on the other hand, I got a little bored because I had expected information about the Heroes of Olympus series (because of the subtitle). Part of this information was exactly how these gods, goddesses, and creatures were created and how their offspring were created. The main thought in my head as I read this book was, Wow...the Greeks and Romans were really messed up. Yes...it's pretty awkward and kind of gross, so consider yourself warned. Because of this stuff that makes up quite a bit of the book, I wouldn't recommend this book to anyone under 14/15 (that's my bare minimum).
However, there was some speculations here and there about what creatures might appear in the next Heroes of Olympus books; much less than what I expected, so I was disappointed about that. I found some of these speculations amusing because I had already started the second Heroes of Olympus book, The Son of Neptune at the time I read this book, and, therefore, I could see which of these speculations were proved wrong by that point in the series.
How will I rate this book? The physical stuff (if you read my meaning) definitely will take some points off, in addition to my disappointment from the misleading subtitle. So, in the end, my rating is:
Alyianna's rating: 7 out 10
(You may notice that I tagged this post as both "media to stay away from" AND "okay-ish". That is because I am trying to make a point that it all depends on the reader and what they deem is appropriate.)