Ash is an important and yet understudied aspect of ritual deposition in the archaeological record of North America. Ash has been found in a wide variety of contexts across many regions and often it is associated with rare or unusual objects or in contexts that suggest its use in the transition or transformation of houses and ritual features. Drawn from across the U.S. and Mesoamerica, the chapters in this volume explore the use, meanings, and cross-cultural patterns present in the use of ash. and highlight the importance of ash in ritual closure, social memory, and cultural transformation.