(Spirit Rock Meditation Center) We review at the beginning the basic instructions for cultivating concentration (samadhi), including attention to posture, a variety of possible areas of focus (with most attention given to the breath, including the technique of practicing with the "three-part breath"), and balancing "not too tight" and "not too loose." We also review the main challenges that can arise in such practice, and how to work with these challenges. Then we practice mostly in silence, with a discussion period at the end of the sitting.