Chemical processes are a crucial part of chemical engineering. They refer to naturally and artificially changing one or many chemical compounds. Process control of chemical processes is an operation of controlling and supervising the optimal and safe use of chemicals and chemical reactions in factories and plants. The processes generally monitored in industrial plants are hydration, oxidation, nitrification, reduction, catalysis, etc. This book is a compilation of chapters that discuss the most vital concepts in the field of process control and instrumentation with respect to chemical engineering. It includes a detailed explanation of the various concepts and applications of this subject. This textbook will serve as a reference to a broad spectrum of readers.