Received as one of my Xmas presents, a book well worth adding to your library,
Although nominally for the TYW period in europe the bulk of the content is relevant for the ECW as well. It comprises ~290 pages full of illustrations covering cavalry, infantry, artillery, supply train, camps, river crossings, fortifications etc.
I have the one published by Partizan Press, available from Caliver Books; Warlord Games also publish it, see their Pike and Shotte books section. These are both paperback reprints, the original hardcover can be obtained but is a tad expensive.