Each human being is motivated by needs. Our most basic needs are inborn, having evolved over tens of thousands of years. Abraham Maslow's Hierarchy of Needs helps to explain how these needs motivate us all.

Maslow's Hierarchy of Needs model was developed between 1943-1954, and first widely published in Motivation and Personality in 1954. At this time the Hierarchy of Needs model comprised five needs.

Physiological Needs

These are the very basic needs such as air, water, food, sleep, sex, etc. When these are not satisfied we may feel sickness, irritation, pain, discomfort, etc. These feelings motivate us to alleviate them as soon as possible to establish homeostasis. Once they are alleviated, we may think about other things.

Safety Needs

These have to do with establishing stability and consistency in a chaotic world. These needs are mostly psychological in nature. We need the security of a home and family. However, if a family is dysfunction, i.e., an abusive husband, the wife cannot move to the next level because she is constantly concerned for her safety. Love and belongingness have to wait until she is no longer cringing in fear. Many in our society cry out for law and order because they do not feel safe enough to go for a walk in their neighborhood.

Love and Belongingness Needs

These are next on the ladder. Humans have a desire to belong to groups: clubs, work groups, religious groups, family, gangs, etc. We need to feel loved (non-sexual) by others, to be accepted by others. Performers appreciate applause. We need to be needed. 

Self-Esteem Needs

There are two types of esteem needs. First is self-esteem which results from competence or mastery of a task. Second, there's the attention and recognition that comes from others. This is similar to the belongingness level, however, wanting admiration has to do with the need for power.
 

The need for Self-actualization

This is "the desire to become more and more what one is, to become everything that one is capable of becoming." People who have everything can maximize their potential. They can seek knowledge, peace, esthetic experiences, self-fulfillment, oneness with God, etc.
 

Maslow's most popular book is Toward a Psychology of Being (1968), in which more layers were added. The original 5 layer-version still remains for most people the definitive Hierarchy of Needs.