The Understanding by Design Guide to Creating High-Quality Units, written by Grant Wiggins and Jay McTighe, is a companion book to Understanding by Design. It provides educators with a step-by-step guide for designing units of instruction that align with the principles of Understanding by Design. The book offers practical tips, examples, and templates to help educators create coherent and engaging units that promote deep understanding and transfer of learning. It also addresses common challenges and provides strategies for assessment and differentiation.