The vast majority of games of interest in economics, finance, political economy etc. involve some form of payoff uncertainty. A simple but interesting example is provided by auctions: an object is offered for sale, and individuals are required to submit their bids in sealed envelopes. The object is then allocated to the highest bidder at a price which depends on every bid, according to some prespecified rule (e.g. \first-price\ or \second-price\rule). In