This book represents research-based best practices related to each and every aspect 8051 microcontroller. The target audience for this book includes students, beginners, software as well as automation engineers, professionals, researchers, and professors. This book provides a best way to learn programming, interfacing & application of 8051 microcontroller The book contains a large number of solved problems & programs at the end of each chapter. Detailed and step-by-step solutions to these 8051 microcontroller programs are provided to help students as well as researchers to learn problem-solving techniques. It presents a specific set of solutions, mostly obtained from real world projects and experimental studies, for routine applications. It further highlights promising emerging techniques for research and exploration opportunities in microcontroller fundamentals area. The concepts of 8051 microcontroller are simplified without losing the beauty of the ideas involved. Emphasis has been given to an understanding of the basic microcontroller concepts and their applications to a number of engineering problems. Each topic has been discussed in detail, both conceptually and programmatically, so that learners do not face any kind of difficulties.