There are many different types of decisions - from the important and life-changing to the mundane and everyday - but all are important for our functioning as humans. This book offers an accessible guide to the complex process of human decision-making, tailored for both undergraduate and graduate students. It combines recent research with real-life examples to provide a comprehensive understanding of the underlying biology of decision-making, its relationship to cognitive abilities such as working memory, executive function and attention, and its intersection with development. The book also explores applications and theories of decision-making, giving readers a broader perspective on the field. Presented in an accessible format with in-depth explanations, the work provides everything needed to build a strong basis of understanding of the underlying biology to the more complex topics of how decision-making develops and impacts on other behaviours. Discussion points are included throughout to encourage deeper reflection on the content covered.