There is no definitive way to find everything that a particular author has ever published, but here are some tips:

• To find journal articles, start with an author search in PubMed. Type in the author last name first, followed by first initial, followed by [au]. For example, for Jean Alice Smith, use Smith JA[au]
• Other author search sources are: Web of Science and Scopus. They both incorporate Author searches: Just follow their instructions on the respective pages.
• For books, an author search in WorldCat would be a great place to start. WorldCat also indexes some book chapters.