From leading clinical researchers, this book presents important advances in understanding and treating the early social-communication difficulties that are hallmarks of autism spectrum disorders (ASD). It is grounded in current findings on typically and atypically developing infants, toddlers, and preschoolers. Contributors highlight the connections between ASD and impairments in joint attention, communication and language, play, and imitation. They review approaches to supporting children's functioning in each area, along with evidence-based screening and assessment strategies. Valuable advice is offered on matching treatment to individual children's needs. The book also explores the developmental and neurobiological processes that underlie social-communication deficits in ASD.