Anxiety refers to an emotion characterized by an unpleasant state of inner conflict and subjectively unpleasant emotions of dread over anticipated events. Nervous behavior, such as pacing back and forth, somatic complaints, and rumination accompanies anxiety. It is a feeling of uneasiness and worry, generally unfocused and generalized as an overreaction to a circumstance that is subjectively alarming. A mental state characterized by a poor mood and aversion to activity is referred to as depression. Anhedonia is the key symptom of depression. It refers to a loss of interest or decreased feeling of pleasure in certain activities that normally bring happiness to the individuals. Stress is an organism's reaction to a stressor, such as an environmental situation, which can be physiological, biological, or psychological. It is the body's response to a situation that includes a threat, a challenge, or a physical or psychological barrier. This book explores all the important aspects of stress, anxiety and depression in the present day scenario. It will serve as a valuable source of reference for graduate and post graduate students.