This is my first ever talk as a zen teacher. It is my commentary on case 45 of the Gateless Barrier, “Who is That Other?” My reading of this Koan is that it goes to the heart of our Zen practice: that is, it asks the question, how do we integrate our understanding of the oneness and interdependence of life, which we discover in Zazen, with how we conduct ourselves in our everyday life embedded as it is in wealth inequality, discrimination based on gender, race, age, sexuality, and ability differences? That is, when we come down from the mountain of Oneness, how do we conduct ourselves in our relationships with our partners, our families, our friends, our work colleagues and indeed, with the homeless person on the street? So, who is that other? Who am I?