This is a beautiful Arts and Crafts/Mission style desk, with wear consistent with its age. 
The Arts and Crafts movement emerged in the late 19th century as a reaction against industrialization and mass production. It emphasized handcrafted goods and simple, functional designs. Mission style, a subset of Arts and Crafts, is characterized by its sturdy oak construction, rectilinear forms, and minimal ornamentation.
These desks were often used as library tables or writing desks, reflecting the movement's emphasis on intellectual pursuits and craftsmanship. The vertical slats on the legs are a common design element in Mission style furniture. The value of these desks depends on their condition, originality, and the maker.
This one measures
48” W x 28” D x 30” T