This dissertation collects three essays on microeconomic theory. The first chapter studies a new robustness concept in mechanism design with interdependent values: interim dominant strategy incentive compatibility (IDSIC). It requires truth-telling is an interim dominant strategy for each agent, i.e., conditional on her own private information, the truth-telling maximizes her expected payoff for all possible strategies the other agents could use. In a simple setting with two alternatives and no transfers, we characterize IDSIC together with two other well studied concepts: dominant strategy incentive compatibility (DSIC) and ex post incentive compatibility (EPIC). While both DSIC and EPIC permit only constant mechanisms in sufficiently rich environments, non-constant IDSIC mechanisms exist in any environment. The characterization of IDSIC suggests a simple class of (indirect) binary voting rules: Each agent reports Yes/No. Moreover, if the binary voting rule is also additive, then the indirect mechanism is versatile: It admits an interim dominant strategy equilibrium on all payoff environments and all corresponding type spaces. This chapter is based on the working paper “Robust Binary Voting” (Feng and Wu, 2020). The most critical issue in evaluating policies and projects that affect generations of individuals is the choice of social discount rate. The second chapter shows that there exist social discount rates such that the planner can simultaneously be (i) an exponential discounting expected utility maximizer; (ii) intergenerationally Pareto—i.e., if all individuals from all generations prefer one policy/project to another, the planner agrees; and (iii) strongly non- dictatorial—i.e., no individual from any generation is ignored. Moreover, to satisfy (i)–(iii), if the time horizon is long enough, it is generically sufficient and necessary for social discounting to be more patient than the most patient individual’s long-run discounting, independent of the social risk attitude. This chapter is based on the paper “Social Discounting and Intergenerational Pareto” (Feng and Ke, 2018). The third chapter studies a decision maker DM who faces a binary choice. DM does not know which alternative is better, but a group of experts do. However, the experts would like DM to make the wrong choice. Given the opposing preferences, is it still possible for DM to extract useful information from the experts using mechanism design? We answer “Yes”: There are mechanisms where truth-telling is a Bayesian or even ex post equilibrium, even though the information leak benefits DM and hurts the expert. On the other hand, if truth-telling is required to be an interim or ex post dominant strategy, then no mechanism extracts information in favor of DM. This chapter is based on the working paper “Getting Information from Your Enemies” (Feng and Wu, 2019).