If you just need to use the eBook during a single session to browse or use for research, you don't need to download it. EBSCO eBooks allow an online view whcih allows you to browse the book without downloading it or moving it to a device. This is useful if you are browsing books for information as you might a journal article.
In EBSCO, click the "eBook Full Text" link to preview the book online.
The preview allows easy browsing through a clickable table of contents (which will usually have an index), navigation arrows, and cut/paste ability.