This document provides an introduction to the NetBSD kernel. It discusses NetBSD's history and focus on portability across architectures. Key features of the NetBSD kernel discussed include its process scheduling, SMP support, threading model using scheduler activations, and event notification using kqueues. Debugging support via DDB and KGDB is also summarized. The document provides a brief overview of NetBSD's build system and configuration, and notes some limitations in device support. It concludes by highlighting NetBSD's clean code, documentation, and commercial support options.