Bookcase - Wood - sturdy folding step stool

Wonderful folding library stepladder in solid patinated wood (probably oak or ash), from the late 19th or early 20th century.
This model is distinguished by its elegant architectural structure and its remarkable stability. It features four wide rungs leading to an upper openwork, lattice-like platform, originally ideal for resting large-volume books.
The rear trestle-style frame is solidly articulated by its original brushed metal fittings, allowing smooth folding for compact storage.
Good overall condition. The piece has retained a warm, deep patina, enhanced by light signs of use that attest to its authenticity. Sound, stable and robust construction. The wood has been cleaned and waxed.