An analysis of human errors in complex work settings can lead to important insights into the workspace design. This type of analysis is particularly relevant to safety-critical, socio-technical systems that are highly dynamic, stressful and time-constrained, and where failures can result in catastrophic societal, economic or environmental consequences. Some examples of such systems include an airplane cockpit, the stock market, a hospital, and a nuclear power plant. The research described in this dissertation focuses on advanced trauma care, an additional example of a socio-technical system in which medical teams use complex work processes while treating severely injured patients early after injury. Despite advances in trauma care over the past few decades, errors are still observable, even among the most experienced teams. This dissertation focuses on teamwork errors. It identifies and analyzes why, when, and how teamwork errors occur in trauma resuscitation. The objective was to gain deep insights and knowledge of the work of trauma teams to inform the development of information technologies to support teamwork and detect and prevent errors. Through an extensive ethnographic study and a mixture of techniques including cognitive work analysis and grounded theory approach, four team error types were identified. These include: interpretation errors, caused by inefficient evidential data integration; communication errors, caused by failures to report critical patient information; management errors, caused by inefficient tracking of the progress of multi-step procedures; and, concurrency errors, caused by parallel activities over the shared resources. Findings from this study have broader applicability to other collaborative and highly dynamic work settings that are prone to human error. This work contributes to the fields of Information Science and Computer-Supported Cooperative Work by adding to the understanding of collaborative information seeking in large collocated teams; identifying the challenges and opportunities for information technology support of teamwork in time- and safety-critical settings; and, providing specific recommendations for technological support of teamwork in trauma resuscitation, a domain of great societal importance. [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.]