introduces the key areas in the field, including multilingualism, the role of teaching, the mental processing of multiple languages, and patterns of growth and decline explores the key theories and debates and elucidates areas of controversy gathers together influential readings from key names in the discipline, including: Vivian Cook, William E. Dunn and James P. Lantolf, S.P. Corder, and Nina Spada and Patsy Lightbown.
I'm currently reading this as a textbook for a linguistics class and I REALLY like it. (If anything ever qualified me as being a nerd, it's that last statement.) It's written in a clear, accessible manner that makes it almost possible for me to understand the abstract concepts of linguistics and SLA research.
Found the mix of theoretical overviews, in-depth research articles, and workbook like activities or tasks to be very novel. More books like this please!!