All of the eBook authors in 123Library are cross-referenced. When you view an eBook details page, you can see the author's name under the “Product details” heading. When you click on this, all of the eBooks by that author are listed.
Alternatively, it is possible to construct a search for an author by using the URL format:
In this case, substitute your search for “Smith”, remembering to replace spaces with a “+” symbol.