Early in my surgical training, one of my mentors, Dr Ray Kuretu, stated, ''Knowledge is not knowledge unless it is knowledge.'' This statement impressed upon me the need to learn, retain, and be able to use information for the benefit of my patients without having to return to a textbook or repeat a mistake. This is possible during one's surgical training largely because of repetition and experience. Unfortunately, repetition and experience take a bit longer to acquire with the current constraints on training. These include reduced work hours, intense scrutiny of outcomes, public reporting, and the highly technical expertise (and stakes) necessary for success in cardiothoracic surgery. To improve surgical education and supplement some of the necessary experiences, simulation and boot camp experiences have emerged. In this issue of the Journal, Kenny and colleagues 1 have proposed these as important parts of training the cardiothoracic surgeon of the future. Kenny and colleagues 1 evaluated 20 first-year cardiothoracic trainees on 2 procedures (pulmonary wedge resection and cardiopulmonary bypass) before and after 2 boot campstyle courses. The first course used simulators and cadavers and the second used live animals for an operating simulation. Performance was evaluated by surgical trainers with Objective Structured Assessment of Technical Skills matrices before and after each course. In addition, clinical supervisors were asked to evaluate trainees after the courses. Not surprisingly, the mean performance scores improved after participation in both courses for both procedures. Kenny and colleagues 1 concluded that the courses improve technical skills, improve confidence, and should be supported by the surgical community. Interestingly, consistent improvement was not demonstrated in all subskills evaluated after each procedure and each course. Is it possible that the trainees maintained the skills after the first course and therefore had little room for additional improvement after the second, were some trainees slower to learn, or perhaps was each trainee unable to perform each procedure completely? In training cardiothoracic residents, we have all seen variability among