This is an early 20th century, circa 1920, 3-level shelving unit that could be used as a book case or display case that was distributed by the Triangle Furniture Company from Brooklyn. In general, the most desirable book cases from that era were made by Macey or Globe Wernicke. Those were produced with glass door fronts. This shelving unit does not appear to have the hardware for such. The estimate is based on actual recent past recorded auction sales of comparables. Retail 'asking prices' can be higher and vary.