Généalogie de Bertrand de Càumont, de Beauvilla;

[Paris] De L'Imprimerie de D'Houry.. 1757.

First (and only) edition. 4to. 250x190mm. pp. [5], 6-34. Folding "additions to the family tree". Mottled calf, expertly rebacked to style, triple fillet border. At centre of both covers is, stamped in gilt, the de Caumont coat of arms (repeated as the woodcut to the title page). All edges gilt, very pretty gold star and dot patterned endpapers. Both pastedowns have the armorial bookplate of Elize Gulston (Elizabeth Bridgitta Gulston - 1749-1780. See https://armorial.library.utoronto.ca/stamp-owners/GUL001 for details of her arms). Edges and corners a little bumped and lower cover is a slightly stained. Internally very good with some foxing and a slight grey mark to the bottom right corner. Rare, Worldcat locating two copies (BNF and Berlin).
This book is essentially a short, to-the-point legal argument proving the claim of Bertrand de Caumont to the family title and estate following the death at the Battle of Cuneo of the 23 year old Armand de Caumont. The title was created in the eleventh century so the claim was a complex one but, with the help of this book Bertrand was successful and it was no doubt this success that prompted him to have this copy so lavishly bound with his arms.
The ownership of Elize Gulston is also interesting. She was an inventor, scientist and artist who married the connoisseur (and irritant to Horace Walpole) Joseph Gulston. Between them they were enormously rich but managed to plough through their fortune in collecting art, houses and, as this lovely volume testifies, attractive books.