This book focuses on the dynamic relationships among individual difference (ID) variables (i.e., willingness to communicate, motivation, language anxiety and boredom) in learning English as a foreign language in the virtual world Second Life. The theoretical part provides an overview of selected issues related to the four ID factors in question (e.g., definitions, models, sources, types, empirical investigations). The empirical part reports the findings of a research project which aimed to examine the changing nature of WTC, motivation, boredom and language anxiety experienced by six English majors during their visits to the said virtual world, the main contributors to the changes in the levels of the constructs under investigation, as well as their relationships. The book closes with the discussion of directions for further research as well as pedagogical implications.