[Excerpt] The central premise of this chapter is that, as organizations become less important in defining career pathways and boundaries, occupations will become increasingly more important. While occupational demarcations have always had a significant, albeit often unacknowledged, impact on individual career patterns, the significance of such demarcations for careers is likely to be heightened by current trends in employment relationships. In this chapter, then, I review the sociological literature on occupational labor markets and on the structure of professional occupations, in an effort to shed light on a number of issues associated with occupationally based careers. Of specific concern are three questions: What kinds of job and occupational characteristics foster such careers? When occupations become the major locus of careers, what are the consequences for organizations? And finally, what are some of the key career-management issues for individuals pursuing occupation-ally based careers?