Great stuff from the Kobolds (which, no surprise there) and a much-needed addition to the Faerunian draconic ecology for 5e. You don't need to scratch Realmslore very deep to know the gem dragons are important to the history of the Forgotten Realms, and this supplement lays them out for you - including the background and statblock for Sartior the Ruby Dragon, a key figure in the draconic pantheon of Faerun. In addition to the great content, it's a nicely laid-out and formatted product that meshes well with the fifth-edition look and feel. My only quibble is that a printer-firendly version would be nice to have, but that's a small thing. This is a fine example of the best of what the DMs Guild can produce, and at $3.99 for a product from a recognized industry publisher, you can't beat it.