The idea of strategic equivalence is that some auctions which superficially appear to be quite different from each other actually present bidderss with exactly the same set of alternative choices; hence the Bayesian Nash Equilibrium bidding strategies for the auctions will be the same. The first-price sealed bid and Dutch auctions are strategically equivalent: a function of item values that determines optiml bids in the first-price auction also determines the optimal prices at which to stop the Dutch auction clock. The English and second-price sealed-bid auctions are strategically equivalent when bidders item values for the auctioned item are private and independently drawn from the same probability distribution. In that case, bidders have a dominant strategy to bid their item values in the second-price auction and to drop out of the bidding in the English auction when the standing bid passes their values.