Okay, I'm no expert on crumb quilts, but what I think I understand is that crumb quilts are made from your small scraps of cotton fabrics. Crazy quilts on the other hand are made of a large variety of fabrics, many different textures. And are embellished with fancy stitches, ribbons, rick-rack, beads, sequins, buttons, etc. I think both are sewn on a foundation fabric, crazy quilts could have a pattern printed on the foundation or be done randomly.