Organizing refers to methods of distributing physical and symbolic tasks among multiple agents in order to achieve goals. My dissertation investigates the dynamics of organizing in hybrid information processing systems that incorporate both humans and computers. To explain the behavior of these hybrid systems, I develop and partially test a theory of computer-assisted organizing. This theory extends organization theory by incorporating and accounting for distinguishing characteristics of computer systems. Chapter one develops an ecosystem-level theory of computer-assisted organizing that explains the influence of computer systems on the architecture and performance of capabilities. The theory predicts that computer-assisted organizing increases the division of information processing, giving rise to decentralized capability ecosystems where tasks are distributed to specialized, independent organizations. Compared to integrated organizational capabilities, capability ecosystems can handle more complexity, but they are also more fragile. Chapter two investigates the implications of computer-assisted organizing and capability ecosystems for strategic management at the firm level. I propose that strategy in capability ecosystems must take into account the design of firm boundaries and computer systems. Through strategic design of boundaries, computerized routines, and interface options, firms can influence the evolution of the capability ecosystem in ways that create value and capture value for the firm. Chapters three and four elaborate and test a single component of the theory developed in Chapter one: the relationship between computer-assisted organizing and organizational scalability. Chapter three uses resource-based and attention-based views of the firm to derive hypotheses about interactions between computer-assisted work (CAW), strategy, and business growth. I test the hypotheses using data from over two hundred small wealth management firms. The results indicate that CAW correlates strongly with business growth, and that growth aspirations positively moderate the relationship. The data show that the CAW-growth relationship is stronger for firms with complex, customized strategies that require more unstructured problem solving. Chapter four analyzes data from 284 small and medium-sized firms in seven industries. The data show a significant correlation between CAW and revenue growth. Consistent with the predictions of the theory, the analysis also finds that the CAW-growth relationship is significantly stronger for firms in knowledge-intensive industries. [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.]