This book's star rating has been dragged down by a ridiculous ax-grinding one-star review, so this prompted me to even things out a bit.
This a very nice book, which expands on the fluff for the Metallic Dragons in MM2, and adds exotic new species, such as steel, bronze, mithral, orium, cobalt, mercury, and cobalt dragons. It has entries for the Draconian species from Dragonlance, descriptions and stats for famous NPC dragons such as Silvara and Jalanvaloss, as well as stats and fluff for Bahamut himself.
In summary, if you prefer a fantasy world where morality is a bit deeper and more complex than just looking at the shininess of a creatures scales, [...]then I highly recommend this book.