Start your search for secondary sources here:
Use the main LibrarySearch to find books on your topic.
Try an simple search for your terms, like renaissance warfare, then limit to "Books" under "Resource Type" on the left hand side:
Then, check the record of a book to find the correct Subjects, and use those to search for more books:
What if DePaul doesn't have the book, video or article I need?
Click Here for more information about requesting items through interlibrary loan.