The Moon is the planet of the unconscious mind, habits and emotions. The moon rules desire as opposed to ego, need as opposed to expediency or reason. It describes how you feel about yourself, how you handle relationships, and how you emotionally respond to situations and experiences. It describes the flow of your daily functions; physical, emotional, and mental. The moon represents your residence and domestic environment. It rules babies and young children, your mother and other important females in your life. The Moon is the astrological ruler of Cancer. 

The Moon's position in your chart is almost as important as the Sun, but the influence is different. The moon is your emotional life. It relates to immediate emotional responses. It is those reactions instilled by conditioning; the memory and learned habit patterns. The influence of the Moon is more subtle, for it relates to personality beneath the surface; your feelings and your subconscious self. It shows how you react to those around you based on the sum of your conditioned viewpoint and unguarded self-projection. Often, the Moon's place in the chart shows a considerably different side of the nature, a side fostered by emotions, upbringing, and habit patterns that have developed over time. 

(Based on Net Resources)