The major concern of this compiled lecture is to review the works of various scholars around the world. Therefore, theoretical considerations of research issues, language teaching and learning aspects and other self-reflections towards the applications in EFL contexts are necessary preliminaries for all higher level learners. This text presents seven selected issues with clear definitions, characteristics and their limitations and advantages. This review tries to cover seven units with short and clear discussions. The first unit presents the quasi-experimental design and its common characteristics. The second unit discusses the various aspects of correlational research. The third unit emphasizes on content analysis. The fourth, the fifth, the sixth, and the seventh units focus on case study, behaviourist approach, the monitor hypothesis, and Vygotsky’s sociocultural theory respectively.