In the Yoga Sūtra, a prominent text on Dhyānam within Yoga.

“Chapter One is about the Refinement of the practice of Dhyānam;
Chapter Two is about the Preparation for the practice of Dhyānam;
Chapter Three is about the Outcome of the practice of Dhyānam;
Chapter Four is about the Goal of the practice of Dhyānam.”

Link to Series: 108 Sutra Study Pointers