The document provides an introduction to microcontrollers, specifically focusing on the Intel 8051 microcontroller. It defines microcontrollers and distinguishes them from microprocessors by noting that microcontrollers contain peripherals like RAM, ROM, I/O ports and timers on a single chip, while microprocessors require external circuitry. It then describes the architecture and features of the Intel 8051 microcontroller, including its 4KB program memory, 128 bytes of data memory, 32 general purpose registers, two timers, interrupts and I/O ports. Development tools for microcontrollers like editors, assemblers, compilers and debuggers/simulators are also discussed.