The technological breakthrough associated with the spread of quantum computers is just around the corner. This book discusses future technologies from a practical perspective: Microsoft's toolkit and Q# language give you the opportunity to practice quantum computing. In Part I, you will create a quantum device simulator in Python, and in Part II, you will learn to apply new skills in writing quantum applications with using the Q# language and the Quantum Development Toolkit, and in Part III, implement an algorithm that multiplies integers exponentially faster than the best known standard algorithm. The publication is intended for software developers. No prior experience with quantum computing or advanced knowledge of mathematics or physics is required.