The recent AEG L5R products have shown a dedication to consistent excellence that would make a Crane proud. They are clearly working on conceptualising the game from a players perspective and offering titles that really flesh out the world of Rokugan and add to the immersion in their game.
'The Great Clans' is truly staggering in scope and also in the amount of flavour information they offer. The book is predominantly narrative, and general information, with each Clan given a single chapter.
The information presented in each chapter really goes a long way to making each Clan a very distinct entity and showcasing the diversity possible within the scope of each Clan. It generally avoids stereotypes, but does so in a manner that makes NPCs and ancestors more human whilst adhering to the distinct flavour of the Clan. Every Clan is treated to a historical overview of its roots, major achievements and conflicts throughout the history of Rokugan to give players an appreciation for how the Clan grew into its 'present day' format. There is strong attention to detail here with a solid internal consistency, but presented in a manner which is easy to read. Most of the history is presented as stories, with sidebars and additional boxed text providing clarifications or interesting facts. On this note, whoever was responsible for the layout needs to be congratulated. The text is easily broken up by high-quality art, and the text boxes provide something else to draw the eye to snippets of information.
In addition to this, you can expect to find some Alternate Paths for each Clan (I quite liked the Kitsune Ranger), new Schools (like the Daidoji Scout which is currently vying to be my favourite), Ancestors and NPCs (with full stat blocks which could be used for nay range of purposes), new Techniques and even new rules (such as Rural Traps, in the Crane section, which will be really useful).
In summary, excellent content, high quality production values and a book that should be on every L5R table.
[4 of 5 Stars!]