This chapter discusses sensation and perception. It defines sensation as the process by which senses detect stimuli and transmit signals to the brain. Perception is how the brain interprets these signals. The chapter covers the different senses like hearing, smell, taste, touch. It describes thresholds and transduction for each sense. Factors that influence perception like attention, knowledge and illusions are also discussed. The principles of perceptual organization and unusual perceptual experiences are explained.