This chapter focuses on the development of voluntary Tunguska research in the late 1950s and the way that expeditions gave rise to alternative forms of knowledge about the event. It follows an informal group known as the Complex Amateur Expedition (KSE) that began making annual trips to the taiga: first to test the alien spaceship hypothesis and later to exhaustively investigate the site for any clues about what might have happened there. An array of other voluntary groups became involved as well, with different camps advancing their own contradictory explanations. After the Soviet Academy of Sciences decided to propose that a comet had caused the explosion in the early 1960s and ended its own research, unofficial efforts led the investigations on Tunguska. From this point on, Tunguska was a zone for thinking about the otherworldly at the edge of mainstream science.