I will readily admit that I am a HUGE L5R RPG fan. I've never played the card game, but some of the best campaigns I've ever been on were in the L5R setting, which is saying something considering how much I've played in my home brew D&D and Robotech games over the years. Truly, the only outside game I've played that compares is Shadowrun, and even then I believe I've played more L5R on the whole.
I can well remember going into a Waldenbooks in the early 2000s and finding a copy of the new D20 Oriental Adventures and being very, very excited, only to open it, see the L5R setting, and wonder what the heck just happened. I mean, one of the best factors of L5R is the mechanic [especially the 3rd edition in my opinion], but to have it 'square pegged in a round hole' really put me off.
I swore I wouldn't buy the D20 version, as I already had everything for 2nd Edition, and yet when AEG came out with the 'Secrets' book there was no way not to purchase them. The reasons were twofold. A: They slipped in information for L5R 2nd Edition which made them of immense value to a 2nd Edition player, B: the art direction of Jim Pinto was SO fantastic I still look at these books today in revered wonder, so I had to have the in my collection.
For Secrets of the Mantis, Pinto used cover artist Matthew S. Armstrong [who does the same work for each clan in all the Secrets books] with interiors by one of my all-time favorite illustrators, Cristina McAllister, filling up the pages in lovely sketch-like work. In all, the effect is stunning, simple, beautiful, and right in the perfect zone for pure and adulterated gaming art love. Honestly, I couldn't be happier about a supplement than this book, it is off the charts as far as artistic design.
In total, the book comes in at 95 pages, is filled with solid L5R content, some nice 2nd Edition 'perks', and if you love D20, then it also has tons of that.
Artistic Rating: 5 [out of 5]