1) Fold mailing envelope in half hamburger style. 2) Shave the edges of the three sides opposite the pocket i.e. cut just enough so they are not connected which will make book "pages." 3) Cut in approximately one inch on the crease on each side of the envelope and then place a rubber band around the middle - file sized ones work best. 4) To add papers to the middle make cut ins on each side as you did with the envelope - but less deep. Burrito the papers to slide them under the rubber band.