With the withdrawal of the Runequest II material, this book is now the primary source for creatures in the Legend game. Monsters of Legend has the same monsters that appeared in the previous Runequest II monsters book, with the removal of the chapter on arenas and any Gloranthan monster.
On the positive side, the book does have enough creatures to get you started, and the layout is good, with one monster per page. The digest format makes it a good size to carry around along with the main rulebook. Almost every creature has enough information to be used as a player character, if that is your thing, although the writers advise against choosing non-sapient animals for obvious reasons.
Unfortunately, it is not as well edited as it could be. The description of the Lamia is missing some important text regarding it's kiss weapon, and there are references to Beastmen in the examples, even though there is no representative creature for the Beastmen any longer. Some of the creatures do not have artwork and the table of contents does not list every creature in the book, making it harder to navigate.
The rules for spirit combat were not in the Legend core book, and are included here. A full version of the spirit magic rules, including spirit combat, have since been posted on the Mongoose site.
In summary, it's a useful book that's let down by less than stellar editing. It will be interesting to see if a future version corrects the missing entry and the references to Gloranthan monsters that no longer "exist".
[4 of 5 Stars!]