  We study the problem of when to sell an indivisible object. There is a
monopolistic seller who owns an indivisible object and plans to sell it over a
given span of time to the set of potential buyers whose valuations for the
object evolve over time. We formulate the seller's problem as a dynamic
mechanism design problem. We provide a procedure for finding the optimal
solution and show how to check incentive compatibility. We also discuss the
threshold rule from the perspective of optimal stopping.
