The book is written for an undergraduate course on the 8051 and MSP430 microcontrollers. It provides comprehensive coverage of the hardware and software aspects of 8051 and MSP430 microcontrollers. The book is divided into two parts. The first 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 DC motor interfacing. The second part focuses on MSP430 microcontroller. It teaches you the low power features, architecture, instruction set, programming, digital I/O and on-chip peripherals of MSP430. It describes how to use code composer studio for assembly and C programming. It also describes the interfacing MSP430 with external memory, LCDs, LED modules, wired and wireless sensor networks.