The book is about programming embedded systems using microcontrollers. The material of the book is grouped according to the standard stages of development of any software: requirements analysis, design, coding, debugging and testing. The publication is illustrated by examples in C and an analysis of the compiled machine code for two popular Microchip microcontroller families: PIC18 (8 bits) and PIC24 (16 bits). However, these approaches and techniques can be used in programming microcontrollers from other manufacturers.