Our first introduction to Frank Withers came on December 2, 1963. In our earlier sessions, we had never been able to maintain any consistency between one sitting and another. When the Seth sessions began, one session began to instantly reinforce earlier ones. Seth specified that we have sessions twice a week, naming the evenings and the time. Sessions varied from two to three hours each. Sometimes they were longer. We have followed this schedule ever since, and sessions still continue.

p. 11 - How To Develop Your ESP Power, (1966)