This book is an essential guide to using SNOMED CT®. It emphasises SNOMED CT's® importance to healthcare and describes how it is used to improve patient outcomes and deliver more effective healthcare. The book explains the main design features fundamental to using SNOMED CT® as a clinical terminology, and the tools and processes used to develop and extend it. With these foundations in place, it then offers practical advice to implementing SNOMED CT® in a health information environment, highlighting the intrinsic relationship between terminology and information models, and exploring how different types of health data can be represented. The Essential Guide to SNOMED CT® offers guidance on how to customise the terminology for specific usages, by developing value sets, user-friendly terms, and new content. Effective principles and solutions for deploying terminology services, for designing user interfaces, and for storing, exchanging and querying SNOMED CT® data are also explored. The book concludes by discussing the role that SNOMED CT plays in semantic interoperability, and summarising some key messages for anyone using or planning to use SNOMED CT®.