In recent years, genetics has not only gained increasing public attention but has also made its way into related fields such as biochemistry, pharmacy, agricultural science, and medicine, where a fundamental understanding of genetics is increasingly expected. However, for biology students, the pace of knowledge transfer during genetics studies is often too fast. This book therefore presents the essential foundational knowledge of genetics in a compact form. It is intended to serve both as an introductory and learning aid as well as a review resource. While prior knowledge of genetics is advantageous, it is not strictly necessary—those with no background will also find their entry point with this book.