OU R P R I M A RY C O N C E R N I N this chapter is to outline the evolution ofPeter Brook’s ideas on the preparation of actors. Our particular focus is the development of two interrelated qualities that are prerequisites for performers in his own company: a state of openness and immediacy he calls ‘transparency’; and a state of connectedness and responsiveness he calls ‘the invisible network’. As we shall see, both of these qualities are conceived and explored on internal and external levels. Indeed, like self and other, actor and character, performers and audience, for Brook inner movement and external action must always be in a dynamic relationship of exchange.