Set in a future where humanity has expanded into space and colonized other planets, "Ultima Thule" follows the story of a group of space colonists who encounter a mysterious and enigmatic alien species known as the "Jukka." The colonists must navigate the challenges of interspecies communication and diplomacy as they attempt to establish peaceful relations with the Jukka and learn more about their civilization.Mack Reynolds' novel is known for its exploration of themes such as interstellar diplomacy, cultural exchange, and the complexities of human-alien interaction. Through the lens of science fiction, Reynolds offers readers a thought-provoking examination of the potential challenges and opportunities that may arise as humanity ventures out into the cosmos.