A discussion of in-depth interviewing as a method for research on language teaching and learning situates the technique within the continuum of research methodology and differentiates it from quantitative research methods. The strengths and weaknesses of in-depth interviewing are examined, methods of sampling are discussed, and advice on the administration of interviews is provided. Examples are offered from a study of the positive and negative experiences of North American native English speakers and native Japanese speakers who teach English at Japanese universities in relation to key communication styles: Americans' assertiveness, explicitness, and independence, and Japanese indirectness, "nemawashi" (groundwork), and "tatemae" (stated position). It is concluded that the compelling strengths of inductive, intensive, individual, and insightful interviews will propel them to greater popularity and a lighter status in education and other social science fields in the 21st century. (Contains 12 references.) (MSE)