The authors, both members of the Instrument Society of America, teach engineering students to read, understand, and apply the symbols and documents that are used to define a modern industrial instrumentation and control system. For more experienced professionals, insights into using the symbols and documents more effectively are provided. Information on how and why documents are developed, who develops them, and how they are used is also provided. Types of documents discussed include process flow diagrams, piping and instrumentation drawings, instrument lists, specification forms, and location plans.