This dissertation considers three research questions. Why do scientists become postdoctoral scholars (postdocs)? What role do postdocs play relative to other categories of labor in research production? What factors are associated with a postdoc being dissatisfied? The literature review in Chapter 2 summarizes findings about which scientists are most likely to become postdocs, considering characteristics of individual scientists and doctoral institutions. The role of individual motivations in determining which students plan to become postdocs is incorporated into a conceptual model based on the social psychological theory of planned behavior. The theory frames scientists' motivations for postdoc appointments in terms of behavioral attitudes, social norms, and perceived behavioral control, moderated by understanding that a postdoc is expected for a desired career. Chapter 4 models universities' production of life sciences research as a function of capital and labor (doctoral research assistants, postdocs, and faculty). This analysis uses data about 145 research universities from the NSF Survey of Graduates and Postdoctorates, the 2006 NRC Assessment of Research Doctorate Programs, and other sources to estimate a translog production function using seemingly unrelated regression to calculate coefficients of complementarity. Universities appear to utilize postdocs as complements to doctoral research assistants and faculty in research production. In Chapter 5, survey data from 764 postdocs in physical and mathematical, biological, and health sciences are used in an ordered probit regression to estimate effects of individual and organizational factors on the probability that a postdoc will be dissatisfied with an appointment. Postdocs are less likely to be dissatisfied when they find their current research interesting, when the appointment is consistent with interest in a faculty research career, and when the research has an applied element. Surprisingly, being at an institution with a high-quality doctoral program does not seem to prevent dissatisfaction. Mediation analyses indicate that while postdocs in high-quality programs report greater freedom to shape research projects, they interact less frequently with advisors, possibly due to advisors' involvement in research commercialization. Chapter 6 integrates findings with the literature and current topics in science and workforce policy; discusses implications for policymakers, institutions, and scientists; and suggests future research directions. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]