Enhancing Motivation for Change in Substance Abuse Treatment: Treatment Improvement Protocol (TIP) Series, No. 35
Scroll down and in Chapter 1 click on the link titled "A Transtheoretical Model Of the Stages of Change" and read the content of that section. For more information, read Chapter 8, "Measuring Components of Client Motivation" (optional reading).
Click https://www.ncbi.nlm.nih.gov/books/NBK64967/ link to open resource.