Kalamazoo Archtop Guitar. I'm not an expert on these but based on the 14 3/4" lower bout I believe it's a KG-21, made in the 1930s. Solid spruce over solid mahogany, in good condition, especially for its age. One crack on the bass side has been glued and seems solid, other shown cracks appear to be just the finish as the wood isn't moving. Playing nicely but also suitable for further restoration.