Positive psychology focuses on human thriving and optimal functioning. It studies factors that allow individuals and communities to flourish, in contrast to normal psychology's focus on mental illness. This document summarizes key concepts in positive psychology including happiness, optimism, character strengths, and motivation. Happiness is defined as subjective well-being and includes pleasure, life satisfaction. Research shows happiness is correlated with factors like marriage, health, and optimism rather than money. Optimism can be learned and involves explaining events in a way that is external, temporary, and situation-specific for bad events but internal, permanent and global for good events. Identifying and using one's character strengths leads to fulfillment and goal achievement. Intrinsic rather than extrinsic motivation is