Design Techniques for Origami Tessellations is both a collection of origami tessellations and a manual to design them. This book begins by explaining general design methods, the history and definitions of origami tessellations, and the geometric features of flat origami, before moving on to introduce a brand-new design method: the "twist-based design method." This method generates base parts that connect "twist patterns” (that can be folded with a twist) without using a lattice. Therefore, it can generate base parts such as regular pentagons, which cannot be generated with more conventional methods, and can generate new origami tessellations connected to them. Features: No proofs or formulas in the text and minimal jargon. Suitable for readers with a roughly middle school to high school level of mathematical background. Web application implementing the method described in this book is available, allowing the readers to design their own patterns.