The psychology of thinking, a cornerstone of cognitive psychology, explores how we process information, solve problems, make decisions, and form judgments - functions that lie at the heart of human experience. Its roots trace back to early philosophers like Plato and Aristotle, but it gained scientific traction in the 20th century. Jean Piaget (1896–1980) pioneered our understanding of cognitive development in children, while Jerome Bruner (1915–2016) emphasized the role of culture and meaning in thought. In the mid-1900s, the cognitive revolution brought figures like Allen Newell and Herbert Simon, who in 1956 introduced the concept of bounded rationality and laid the groundwork for artificial intelligence. Daniel Kahneman and Amos Tversky, through their work in the 1970s and beyond, revolutionized how we understand decision-making under uncertainty, leading to Kahneman’s Nobel Prize in 2002. These foundational thinkers helped shape our modern grasp of mental processes. The psychology of thinking not only enhances personal wellbeing by fostering self-awareness, critical thinking, and emotional regulation, but it also promotes societal health by improving education, policymaking, and conflict resolution. In understanding how we think, we unlock the potential to think better - more clearly, compassionately, and wisely. To know anyone more fully or closely, including ourselves, is to know how they think, for thought is a primary expression of the human spirit and reflects the condition of our soul at any given moment of time. As the Bible says of us, "For as he thinks in his heart, so is he" (Proverbs 23:7).