Work is something common to all of humanity and it always has been. Throughout human history there have been many major revolutions in the world of work that have changed how people work and the types of things that they produce. The Agricultural Revolution changed how people produced and used food and changed how and where they lived. Similarly, when humans started producing pottery and metal tools and weapons there were additional changes in work and what kinds of things people did to support and protect themselves. The Industrial Revolution resulted in significant changes in the nature of work, but also where people worked and lived and they kinds of products they were now able to produce. More recently, the Information Revolution has also dramatically changed the nature of work and what people do while at work.This paper will review the nature of work and look at this topic as an important part of the psychology of humans and how work has changed over the centuries and millennia and what it looks like today. By work we mean, “A purposeful activity that is intended to facilitate survival, comfort, protection of the society, and self-fulfillment.” In addition to examining the history and evolution of work, this paper examines the functional nature of work and how that has changed and evolved as well. In addition, the motivational basis of work will be examined and the various reasons why people work will also be explored as well. One of the principal foci of this paper will be a thorough examination of how work is changing in the 21st century and looking at how globalization and technology have changed the world of work and the psychological importance of work today.