1. Condition:
- Well-preserved sets with no significant damage are more valuable.
- Look for any issues such as torn pages, water damage, or missing volumes.
2. Completeness:
- A complete set of Funk and Wagnalls encyclopedias from 1979 typically consists of 29 volumes.
- Check that all volumes are present and in the original order.
3. Dust Jackets and Original Packaging:
- If the encyclopedias have their original dust jackets and are still in the original packaging, it adds to their value.
- Well-preserved dust jackets and packaging indicate a set that has been carefully handled and protected over time.
4. Special Features:
- Some editions of the 1979 Funk and Wagnalls encyclopedias may include special features such as index volumes or unique illustrations.
- The presence of these features can increase the value of the set.
5. Collector Demand:
- Vintage encyclopedias can be sought after by collectors who appreciate nostalgia or specialized topics.
- Research any collector interest in this particular edition of the encyclopedia.
6. Regional Market:
- The value may vary depending on the region or country you are located in.
- Availability and demand for vintage encyclopedias can differ by location.
Based on these factors, the value of a set of 1979 Funk and Wagnalls encyclopedias could range from a few hundred dollars for a well-preserved and complete set to over a thousand dollars for an exceptionally rare or unique set. It's always advisable to check online marketplaces, rare book dealers, or book collectors to get a more accurate estimate.