Sesshin - a silent, residential, Zen meditation retreat involving a 24-hour communal schedule - is an extremely valuable way to deepen your Zen practice. I discuss why I strongly encourage you to participate in sesshin, but also why - if you can't do so - it isn't necessary. Then I talk about several of the benefits and Dharma lessons of sesshin. I have many more such benefits and lessons to share, but I'll cover them in Celebration of Sesshin Part 2.