Each combat encounter is presented in a 2-page format with a tactical map and stat blocks included. Basically, the traditional module text, that would have the rooms described in a numbered sequence, is in one section of the book with cross references to the pertinent combat encounters which form another section of the book.
It's quite a bit easier to use than having all of the stat blocks alphabetically in an appendix at the end of the book like with Return to the Temple of Elemental Evil and Shackled City, but it is a fairly expansive amount of space which will probably lead to any further modules using this format to be bulkier and a bit more expensive.
I will admit that having all of the stat blocks, descriptive text setting up the encounter, a tactical map, and pertinent room conditions/rules called out is highly convenient and easy to use at the table-top game session. I've used a few encounters from EtCR in my 3E adaptation of I6 and the format has been pretty nice for it.
THe maps from EtCR are available on Wizards' web site so you can get an idea of the tactical maps involved. Check out the art gallery for the product and you should be able to see them. I'd have liked versions without the monster's starting positions on them so they could be blown up and used directly on the table as battlemaps, but that would be the Cadillac version and I'm happing driving a Tracer.
