The book provides a detailed survey of relevant research and theory on the use of vocabulary learning strategies (VLS) in the field of second (L2)/foreign language learning, and explores the effect of learner-related factors on their effective use in EFL/ESP learning contexts. In order to fill the void in the area of L2 vocabulary acquisition research, it investigates the role of the affective factors of self-regulation and self-esteem in L2 strategy competence in an ESP context and determines their interactive effect in the process when combined with L2 learners' particular learner style by relying on a quantitative data analysis approach. In this light, the study reported in this book empirically redefines the psychological status of self-regulation, self-esteem and learning style in L2 language learning, setting the scene for future extensive research in the area of L2 vocabulary strategy acquisition.