Copyright 1917. This copy is certainly vintage, likely antique. Previous owner name in faded pencil on FFEP. Loose spine with one separated page. I believe this is the format for Grosset & Dunlap first editions of this series. Boards are worn with fraying, tears, stains, bumped corners - see photos. Please see my 2 additional Bobbsey Twins books - all with the same format. (SW2) (10B)