The book is written for an undergraduate course on the 8086 microprocessor and 8051 microcontroller. It provides comprehensive coverage of the hardware and software aspects of 8086 microprocessor and 8051 microcontroller. The book is divided into three parts. The first part focuses on 8086 microprocessor. It teaches you the 8086 architecture, instruction set, assembly language programming (ALP), interfacing 8086 with support chips, memory, and peripherals such as 8251, 8253, 8255, 8259, 8237, and 8279. It also explains the interfacing of 8086 with data converters - ADC and DAC and introduces a traffic light control system.The second part focuses on multiprogramming and multiprocessor configurations, numeric processor 8087, I/O processor 8089, and introduces features of advanced processors such as 80286, 80386, 80486, and Pentium processors.The third part focuses on 8051 microcontroller. It teaches you the 8051 architecture, instruction set, programming 8051, and interfacing 8051 with external memory. It explains timers/counters, serial port, interrupts of 8051, and their programming. It also describes the interfacing 8051 with data converters - ADC and DAC, keyboards, LCDs, LEDs, stepper motors, and sensors.