The book investigates the writing processes of multilingual Moroccan University students writing in two different rhetorical genres in Arabic (L1) and English (L3). It reports on the protocols obtained from eighteen subjects, analyzed both quantitatively and qualitatively, which should help shed light on the effects of the factors of writing skill, discourse type, language, gender, purpose/audience specification, and topic familiarity on the subjects'' composing strategies. It also considers to what extent the subjects'' affect, prior knowledge and awareness of discourse conventions contribute to their understanding of what writing really involves, and affect their approaches to and the quality of their writing. The book also provides a comprehensive discussion of the complex phenomenon of transfer and language-switch which involves the use of up to four languages while composing in English. The composing strategies revealed are presented in a L1/L3 composing process model. This book will be useful to researchers and teachers interested in the composing processes of Arab learners and multilingual writers writing in English as a second or a foreign language.