  I study the optimal provision of information in a long-term relationship
between a sender and a receiver. The sender observes a persistent, evolving
state and commits to send signals over time to the receiver, who sequentially
chooses public actions that affect the welfare of both players. I solve for the
sender's optimal policy in closed form: the sender reports the value of the
state with a delay that shrinks over time and eventually vanishes. Even when
the receiver knows the current state, the sender retains leverage by
threatening to conceal the future evolution of the state.
