1. Condition: The overall condition of the dictionary is important. Look for any tears, stains, or damage to the covers, pages, or bindings. A well-preserved and intact copy is more valuable.
2. Completeness: Ensure that the dictionary is complete and has all the volumes. Any missing volumes can significantly reduce its value.
3. Edition: There were different editions of the Century Dictionary and Cyclopedia published in 1906. Some editions may be more valuable or sought-after than others.
4. Binding: The type of binding can also affect the value. Leather-bound or hardcover copies are generally more valuable than paperback or cloth-bound versions.
5. Rarity: The scarcity or rarity of the specific edition can also contribute to its value. If the 1906 edition is considered rare or hard to find, its value may be higher.
Considering these factors, the value of a century dictionary and cyclopedia from 1906 can range from a few hundred dollars to a few thousand dollars. To get a more accurate assessment of its value, it's recommended to consult with a professional appraiser or dealer specializing in antique books and literature.