Boston cookies are a spiced drop cookie with chopped nuts and dried fruit in them.
They are based on creamed butter and sugar, egg, flour, and a chemical leavener (which originally was baking soda but now may be part baking powder.)
The nuts can be hickory or walnut; the fruit can be raisins, currants, or dates, or a mixture thereof. Dates are a more modern addition.
Modern recipes will also call for a small amount of vanilla extract as flavouring.