This book is a key resource that explains step by step, the essential skills required to rigorously construct and quality assure Logical Data Models. It also defines the processes required for organisations to successfully adopt them, and so align their systems, operations and strategic direction. In the last decade, Data Models have made the transition from being ad-hoc and limited in scope, to becoming a central pillar of the Enterprise Data Architectural landscape. Arguably they are now more important than ever. It is only with a full and agreed understanding of the 'What?', 'When?' and 'How?' of an organisation's data structures and flows, that we can, for example; contemplate plugging COTS products together, implement in the Cloud, ingest data into our Data Lakes, or report across the Enterprise system landscape. No technical background is required to gain a full benefit from the book, it and is relevant for all organisations and data realms. It provides numerous explanations, examples, check lists and templates to provide the reader with a wealth of practical material that will speed their ability to start data modelling effectively and confidently.