The Epic.NET's documentation consists of a comprehensive manual and a detailed API reference built from source code's comments.
The manual describes the framework from an architectural point of view, the patterns that we use in our daily modelling activities and the tools that Epic provides to ease the development process. You might find it usefull even if you are not planning to use Epic, as it aims to complete the blue book with the best solutions we have found to the modelling challenges that we have faced during the last 5 years.
The API reference, on the other hand, describes the implementation details and the common usage of the various tools that Epic provides. It is written with the client perspective in mind and it's open to comment and suggestions.