Beginning with foundational knowledge in genetics and neuroscience, the book progresses to outline genetic risk factors for various addictions, including alcohol, opioids, and gambling. It delves into how genes interact with environmental factors, such as early life experiences, to either amplify or mitigate addiction risk. Furthermore, the text examines pharmacogenomics, or how genetic variations influence drug metabolism, offering insights into how this knowledge can inform personalized treatment decisions. This comprehensive approach provides a nuanced understanding of addiction etiology.