Gita
In addition to Patanjali Yoga Sutras, the Bhagavad Gita is the perfect complement.
The two are the canonical Yoga Shastras.
PYS is incredibly cryptic - like Firmware for the Mind. Bang on when you get it. Sometimes to get it you need a narrative for the sutra - jumping into Gita will surely get the answer - it would be good to cross-link from PY sutras to BG shlokas. There must be a good mapping.
Gita is narrative form - all content from the Upanishads (Vedanta), however the key to Krishna's delivery is the sequence targeted towards different types of mindset that could relate to each chapter. That's why it is called the 5th Veda.
To-Be-Started