Start by typing your keywords into the Everything search box, then click "search."
On the results page, look on the left side of the page for the Books filter. Click it, and your results will reload, displaying only book results. To keep this filter in place for the duration of your session, see instructions here.
TIP: If you don't see a perfect book for your topic, try a slightly broader search. When you find a broader ebook that looks like a good match, search inside it for more specific keywords. You may find a perfect chapter!
See also:
