A lecture given for the first time Is a fragile, tentative thing. It is outlined, footnoted and blotched By irrelevant references. A lecture given a dozen times Grows, develops emphasis, Evolves. Its strong passages Expand, overtaking marginal metaphors, Erasing earlier errors, growing With each giving. Timing is everything -- The same people ask the same Questions at the same places. Even The danger of d'ej`a vu is Superseded by the momentum of The idea. The message and the Messenger merge. A lecture given a hundred times suffers and Gasps and assumes too much. The teacher Must learn from the student, Must take a new vantage, Be excited by discovery. Stop lecturing -- entertain silence, Listen, contemplate, Read, write, rewrite, Reflect, recreate, Relax, renew.