Project Gutenberg has free e-books online, including some Civil War books. As the website explains, books online are those that are in "the public domain". A rule of thumb is books published prior to 1927. Note that the Project Gutenberg books are selected by volunteers--and that is how they are found. You might find Stonewall in this collection.

Sincerely,

Terri A. Hastings
Average e-mail is o.k.