This kind of internal "telepathic" intercourse, which was to serve me in all my wanderings, was at first difficult, ineffective, and painful. But in time I came to be able to live through the experiences of my host with vividness and accuracy, while yet preserving my own individuality, my own critical intelligence, my own desires and fears. Only when the other had come to realize my presence within him could he, by a special act of volition, keep particular thoughts secret from me.

Chapter III: The Other Earth; 1. On the Other Earth (pp. 25-26) - Star Maker (1937)