The Secret Dovetailed Box
Begin by setting your marking gauge equal to the thickness of your stock.
Scratch this distance around the ends and the inside face of the boards.
Connect the corners of the square outlined on the end making a 45 degree line.
Lay out a 1/4 inch shoulder that intersects this diagonal.
Saw and plane this shoulder across the grain on both pieces.
Lay out pins on one piece, sawing diagonally and chiseling out the waste to completion.
Set this piece on the second piece and reach in with a sharp pencil to transfer the dimensions for the tails.
Saw the diagonal shoulders of the tails and chisel out the waste.
Finally, chisel and plane away the square shoulders to a tight fitting miter.
The Complete Book of Woodwork Joints, by Charles Hayward.