Software projects in critical domains cannot afford to fail due to concerns with safety, finances, and other criticality drivers and yet, many do. In the context of this text, we shall refer to software projects in the domains of defense, healthcare, finance, and aviation as critical systems or systems in which, at best, failures result in financial harm or, at worst, loss of life. Whether the failure stems from scope creep, misunderstood requirements, or an inability to adapt to changing stakeholder needs, the root cause is often a breakdown in engineering rigor, over reliance on Agile flexibility, or both.