The library catalogue SOLO is the best place to find individual ebooks. Search for the book you want and if an ebook is available it will appear along with the print version of the book. You may wish to change the drop-down menu from Search Everything to All libraries/collections to avoid book reviews.
From here you can click on the title of the book or See all versions and then click on Online access to read the ebook itself.
If you are only interested in ebooks and not print copies, you can filter your search results using the Show only: options on the left: click Online Resources.