William Lucyshyn, together with Peter Sandborn, recently published a book entitled System Sustainment. This book is an outgrowth of a mixture of courses developed in engineering and public policy at the University of Maryland that treat the acquisition, life-cycle cost, reliability, maintainability, and supply-chain risks associated with critical systems (where critical systems are characterized by high procurement costs, long field lives, severe failure consequences, and a general unwillingness or inability by their owners/stakeholders to replace them). System Sustainment is intended to be a resource for advanced undergraduate and graduate students in engineering, business, and public policy who want to understand the ramifications of, and processes for, system sustainment. “Sustainment,” as commonly defined by industry and government, is comprised of maintenance, support, and upgrade practices that maintain or improve the performance of a system and maximize the availability of goods and services while minimizing their cost and footprint or, more simply, the capacity of a system to endure. System sustainment is a multi-trillion-dollar enterprise, in government (infrastructure and defense) and industry (transportation, industrial controls, data centers, energy generation, and others). Sustainment isn’t only an engineering problem. Engineering, public policy, and business must all come together in order to appropriately balance risk aversion with innovation and system evolution.