Many business domains are currently transitioning towards a service-dominant business setting. After the transition, business will be centered on the provisioning of solution-oriented, composed services to customers. The emphasis shifts from the value of the individual product or service to the value of the use of products and services in an integrated, customer-focused context - the so-called value-in-use. This requires the integration of the capabilities of multiple service providers and introduces the necessity of explicitly managed, agile business networks. Making the transition to service-dominant business and managing its consequences is a formidable task for any non-trivial business organization. A visionary, well-structured approach is required that has the very basics of service-dominant business at its core. BASE/X is such an approach. This handbook explains how to practically perform service-dominant business modeling following the BASE/X business engineering approach. The contents of this handbook are based on several years of experience with applying BASE/X in several industry settings. This handbook is a must-read for any business designer or engineer moving into a world dominated by customer-centered services.