Know what publication date you are looking for. The most important part of the process is knowing what information you are searching for. Perhaps you are looking for a book from a specific historical era or a specific edition of a book that contains out-of-print material. Whatever you are trying to find, know roughly what era the book is from. Exact dates are not necessary.
Select a search engine. Several search engines exist online specifically for books. Amazon.com allows you to search books that it carries as well as out-of-print books and books being resold through affiliates. The Google Books search engine is a comprehensive online catalog. Barnes and Noble's website also has a search engine, and the used and out-of-print search function allows you to search by date.
Pull up the advanced search feature. Amazon.com, Barnes and Noble and Google allow you to search for books by publication date, but only through their advanced search function. Click "Advanced Search" on the search page to pull this up.
Enter the publication date or range. Find the "Publication Date" field on Amazon or Google or the "Published Year" field on Barnes and Noble. Enter the year you are searching for, or a general period of years (for example, 1970 to 1975) into the field. Click the search button and wait for your results.