There are some e-book collections that can be found under the "Primary Sources" tab. In most cases, those books would be considered primary sources, which is why they reside there instead of on the secondary source page.
Browsing the stacks in Morris Library can be extremely helpful when you are looking for additional sources for your research. Most books related to European history can be found on the 3rd Floor of Morris Library and fall under the following Library of Congress classifications:
Q History of Science
T History of Technology
You can also "browse" the shelves virtually by searching by Call Number through DELCAT.