What is the market value of complete world book encyclopedias 1988?

The market value of a complete set of World Book Encyclopedias from 1988 can vary depending on the condition of the books, whether they are hardcover or softcover, and if they include any supplemental materials. On average, you may find a set in good condition selling for around $50 to $100. However, for an accurate estimate, it's best to check online marketplaces or antique bookstores.