This book gives an introduction to the programming language Structured Text (ST) which is used in Programmable Logic Controllers (PLC). The book can be used for all types of PLC brands including Siemens Structured Control Language (SCL) and Programmable Automation Controllers (PAC). This 3rd edition has been updated and expanded with many of the suggestions and questions that readers and students have come up with, including the desire for many more illustrations and program examples.The book contains more than 150 PLC code examples with a focus on learning how to write robust, readable, and structured code. The book systematically describes basic programming, including advice and practical examples based on the author?s extensive industrial experience.