Triplanetary is a space opera novel by E. E. Smith, best known as the opening work in his classic Lensman universe. The novel presents a sweeping future history of humanity and interstellar conflict, beginning in the early 20th century and extending into deep space warfare. It introduces the idea that Earth is already part of a larger cosmic struggle between powerful alien civilizations. A central element is the secret battle between human-aligned forces and a manipulative alien species known for controlling events from behind the scenes. Early sections of the book are set on Earth, involving espionage, hidden agents, and advanced technology, before expanding into interplanetary and interstellar conflict.
