Dear Jonathan,

Thank you for contacting Mearto with your appraisal inquiry again.

The presented object appears to be four volumes of the History of Europe written by Archibald Alison.
Comparable objects were recently offered and sold on the international auction market.
This piece is in bad to medium condition and no severe damage is visible in the images provided.
A fair market estimation would be between 5 to 10 USD each.
This estimate is based on actual recent past recorded auction sales of comparable items. Retail "asking prices" can be higher and may vary.

With kind regards,
Gregory