This Radiolab episode delves into the fascinating history and current efforts to communicate with dolphins. It features interviews with Margaret Lovett, who, in the 1960s, lived with a dolphin named Peter in a flooded apartment as part of John Lilly's controversial experiments. We also hear from Dr. Denise Hersey, who is now leading a project aimed at creating a two-way communication system with wild dolphins using their unique signature whistles and a wearable underwater computer. While Lilly's ethically questionable methods failed to yield publishable results, Hersey's focus on observation and mutual learning in the wild presents a more hopeful avenue for interspecies communication, despite the slow and challenging progress.