Book excerpt: Dynamic Assessment (DA) reconceptualizes classroom interactions by arguing that teaching and assessment should not be distinct undertakings. This book offers a much-needed coherent framework for co-constructing a ZPD with learners in order to simultaneously reveal the full range of their abilities and promote development. DA has a long history in education but it is new to the L2 field. This book provides the first book-length treatment of DA in the language classroom.