This book presents an IT service-based enterprise solution architecture that bridges the gap between traditional solution architecture and enterprise architecture in a holistic yet pragmatic modeling approach. It aims for ease of use and flexibility to better tackle IT system uncertainties and reduce the cost of change. This book is written by and for the practitioners without finicky definitions. Exemplified with a walk-through case study, the modeling framework helps externalize various stakeholders' mental needs by correlating relevant architectural elements, placing functional services in the characterized containers (including cloud environment), and running through optimal solutions. By leveraging the model's architectural thinking mechanism, IT architects can explore architectural solutions from both structural and decisional schools of thought to grasp real problems and progressively shape or reshape the systems for a larger or ever-changing context.