This is the first of two chapters that present the core ideas of Motivational Systems Theory (MST), along with supporting evidence that has continued to accumulate not only for MST concepts and principles but also for the broad range of motivation theories developed during the second half of the twentieth century that inspired the development of this integrative framework. Humans evolved to be goal directed, and motivational patterns are organized around goals and contexts. So, the first step in understanding human motivational systems is to dive deeply into the science of personal goals. Metaphorically, our core personal goals are the “leaders” in “motivational headquarters.”