One of the biggest challenges we face in healthcare is how to educate and train healthcare professionals without endangering patients-especially when we are teaching the management of high-stakes situations such as codes, trauma care, chest pain, or anaphylactic shock, in which any delay in treatment threatens the outcome. Often, new healthcare practitioners enter their profession without ever having seen-much less gotten experience with-many high-risk/low-volume patient conditions. The use of simulation is growing exponentially in academic and service settings. Simulation can enable students, new graduates, and experienced clinicians to develop clinical competence and confidence in caring for patients in a learning environment that is cognitively and emotionally realistic and safe for the learner-and does not compromise patient safety or outcomes. Simulation can be applied to many clinical situations-far more than a learner can be exposed to in a live clinical environment. Simulation activities need not be bound by one profession, time, or place. Simulation can be expanded to include the systems dynamics of care, interprofessional teamwork, and considerations for hospital technology and equipment at any point in the healthcare continuum. In a clinical setting, simulation can be used to onboard new graduates and experienced staff. Simulation also offers the ability to objectively assess the performance of healthcare professionals based on a well-defined standard of practice. Many organizations carefully assess the competency and performance of new staff, but-other than perhaps yearly skills fairs-do little to ensure that existing staff continue to meet standards of practice and follow evidence-based and best practice processes and protocols. Renewing nursing or medical licenses generally requires only paying a fee and completing continuing education programs-not demonstrating continued competence. Simulation can be developed for continued development of staff and educators. Although we know much more about healthcare education today than we did 20 years ago, much has yet to be discovered. Research is changing healthcare practice on an almost daily basis. Simulation can be used to improve an organization's ability to ensure that all its clinicians maintain competence. Knowing is not doing. Simulation can demonstrate the successful application of knowledge. There is also growing evidence that simulation is effective in developing, assessing, and improving the performance of healthcare teams.