Microcontroller evolution has led to the birth of many embedded products that we use in our daily life. The capability of programming a chip to perform a dedicated functionality has tended to enormous opportunities for solving complex problems that are faced by the industry. An 8051 microcontroller is one of the most important building blocks in various applications and its existence in the market for the last three decades clearly signifies its capabilities and importance in the world of embedded systems. An 8051 microcontroller may not be the most adverse microcontroller that exists in the market today but learning the fundamentals of this microcontroller really helps to upskill and take on any other microcontroller learning path. This book has been written in such a manner that the beginners will find it easy to follow along and embedded enthusiasts with the experience of working with microcontrollers will find various hands-on examples that are relevant from the practical applications point of view. The book covers both assembly language as well as C language programs so that the readers can learn the art of programming 8051 microcontrollers in a user-friendly language C and also the Machines specific assembly language. Keil IDE is used in this work for programming the 8051 microcontrollers and every program that is incorporated in the Book has been tested on the hardware. This means that the readers can take the courts provided in the book as ready referred and can modify them to suit their application needs.