Finally, Dragon-Bloods get some love!
In all seriousness, this is a great addition to any Exalted game, but especially those with Dragon-Blooded PCs. The Thousand Correct Actions refers to an in-setting manual of military practice, which is one of the most important texts in a Dragon-Blood's life, after the texts of the Immaculate Order, making the setting information and flavor text in this book vital to the portrayal of Dragon Blooded characters and the Realm they come from. Given how unsympathetically Dragon-Bloods are portrayed in most of the other Exalted books, a turn to put them in the spotlight as the heroes was due, and the book delivers, flavorfullly and mechanically.
The rules in the book have to do with providing entirely new charms (on average, one new charm for each skill, with some of the more military-themed skills getting multiple new charms) and clarifying, or outright fixing, problematic charms from the Manual of Exalted Power: The Dragon Blooded.
In all fairness, the fixes for existing charms are also part of the free errata issued for the game, but the new charms do a lot to fix balance issues with Dragon Blooded characters as well, and putting the errata into this book is extremely convenient and speeds up my own Exalted game (which stars an all-Dragon-Blooded cast) considerably.
I would go so far as to say The Thousand Correct Actions is essential for the full Dragon Blooded experience, and rekindled my own interest in Exalted right when it was beginning to wane.