This repository is a personal study collection focused on Windows internals, combining condensed book notes (Windows Internals 6th/7th ed., Windows System Programming, .NET IL Assembler) with standalone sample code for Windows kernel drivers and user-mode utilities. The code is not a cohesive application but rather multiple independent Visual Studio projects demonstrating key Windows API patterns: WDM driver skeletons (skeleton, dispatch pass-through, IOCTL handling, keyboard filter, file system filter) and user-mode examples (heap enumeration, singly linked lists, Authenticode signature verification). The material is educational in nature, targeting developers and researchers learning Windows kernel-mode programming and system internals. While the code is functional and well-commented, it relies on the older WDM model and some deprecated API patterns, reflecting a ~2017 vintage. The file system filter driver and keyboard filter driver exhibit non-trivial driver engineering patterns that can serve as reusable templates, though they require the Windows Driver Kit to build. No tests, CI, or deployment configurations exist; the repo is purely a reference and learning resource.