What's that in your pocket? I've included this little origami envelope in most of my instructional books because it makes a good pocket you can easily attach to a larger book. You can also use it alone and slip a little square book, card, or tag inside. Or bind several together to create a a book with all pocket pages. For content, think about what you carry in your pockets, a favorite article of clothing with pockets, memory of clothing with pockets, or a narrative about a hidden secret.
Try making square versions of these books and cards to slip inside the envelope: X book (32), Shorts book (35), Pants book (36), Snake book (39), Twist card (43) Miniature Tied binding (shown above, 65). The Origami Pocket itself is also shown (186). Page numbers are from Making Handmade Books.