This article reviews qualitative studies on discharge and patient care transition processes to understand the barriers to knowledge transfer and to propose principles for information systems for facilitating effective care transitions. Knowledge transfer occurs at many points during the processes, but this review focuses on two critical boundaries: (1) between patients and providers and (2) among various inpatient and outpatient providers. Failure to manage knowledge flows at these boundaries during care transitions can lead to unnecessary patient readmissions. However, interventions to improve processes and outcomes of care transitions have achieved mixed results. Our preliminary findings highlight trust-related barriers to knowledge transfer that might help to explain the mixed results. Analysis also suggests a lack of consideration for information technology's role in building trust during care transitions. We propose trust-enhancing principles for information systems design to better enable knowledge flows in patient-provider and provider-provider relationships.