Antique 3-in-1 Mahogany Dining Table & Desk

Measures fully closed (game table/desk size), 40" wide x 20" deep x 30.5" tall. Middle size measures 38" deep x 40". Full is 75.5" long x 40". Chairs measure 35" tall, 16" seat depth. Floor to seat is 18", top width is 18", seat to top of chair is 18". One captain chair. 

Your pretty dining table, which cleverly folds to a game table, and its unique sliding mechanism, known as the "Watertown Slide" was made in the 1950s - 1960s by the Watertown Table-Slide Corporation, in Wisconsin, quite a famous operation that took out a patent for this unique mechanism for extendable tables as far back as 1889, but with many modifications since then.
We know it has to be older than 1973 because that was the year the company discontinued making their slides out of wood. Post-1973 all slides were made of steel and/or aluminum. We also know it has to be newer than 1953 which is when the company began styling itself as the Watertown Table-Slide Corporation -as per the stamped label on yours. Prior to that it was the Watertown Table-Slide Company.
Interestingly, the company only made the sliding mechanism, the table would have been made elsewhere, most likely at one of the numerous furniture factories in the region.
It's made in the "Hepplewhite" style with straight legs, square sectioned and tapered, typical of the Federal period. Additional ornamentation includes the molded bow edge to the top and the reeded arch decoration on the apron and the curved brackets with open spandrels bracing the tops of the legs.
The chairs are also late-Federal-revival period (typical of the style from 1810 - 1830) with their distinctive stylized and carved fleur-de-lis backsplats.

Minor wear for a table of this age.