This book provides a fresh look at areas of common interest to both second language acquisition (SLA) and language testing  research (LT), and ways in which research in these two areas of applied linguistics can be fruitfully integrated.  The volume includes original papers, especially written around a common theme, dealing with different aspects of the interface between SLA and LT research, by leading researchers in these areas.  This collection thus constitutes a starting point for a continuing and expanding dialogue between SLA and LT researchers.