" This process of linking differentiated parts into a functional whole is called “integration.” As we’ll see, integration is a unifying principle that will help us to understand the linkage of mind, brain, and relationships throughout our discussions. Furthermore, in IPNB, we propose that integration is the heart of health. Linking differentiated parts into a functional whole is called “integration. "

― Daniel J. Siegel , The Developing Mind: How Relationships and the Brain Interact to Shape Who We Are