This open access book, the Community of Practice led by the VPH Institute, the Avicenna Alliance, and the In Silico World consortium has brought together 138 experts in In Silico Trials working in academia, the medical industry, regulatory bodies, hospitals, and consulting firms. Through a consensus process, these experts produced the first attempt to define some Good Simulation Practices on how to develop, evaluate, and use In Silico Trials.  Good Simulation Practice constitutes an indispensable guide for anyone who is planning to engage at any title with In Silico Trials.