We study contests for innovation with learning about the innovation’s feasibility and opponents’ outcomes. We characterize contests that maximize innovation when the designer chooses a prize-sharing scheme and a disclosure policy. A “public winner-takes-all” contest dominates public contests—where any success is immediately disclosed—with any other prize-sharing scheme as well as winner-takes-all contests with any other disclosure policy. Yet, jointly modifying prize sharing and disclosure can increase innovation. In a broad class of mechanisms, it is optimal to share the prize with disclosure following a certain number of successes; under simple conditions, a “hidden equal-sharing” contest is optimal.