This book is a collection of the best, carefully selected articles from the legendary magazine "Hacker" . Windows 11 and Linux operating systems are considered from the point of view of organizing effective work on the PC. Useful applications for these OSes are described, utilities for working in the terminal. Described about programs for steganography - hiding useful data in graphic images. Practical advice for Windows 11 users on remote installation of the OS, disabling telemetry, removing programs and components, fine-tuning the system, optimizing it to work on incompatible and outdated equipment Various Linux settings for safe operation are described in detail. Examples of construction of a home-made case for PC, installation of a supercapacitor in a wireless mouse, assembly of a home-made laptop are presented. Here is an overview of the capabilities of Apple devices based on Ml processors and tips for their effective use.