Mission of Gravity
Hal Clement
 The native protagonist, Barlennan, captain of the Bree, is on a trading expedition to the equator, where the gravity is a tiny fraction of what his culture is used to. Prior to the story's opening, a human scientific probe has become stranded at one of the planet's poles, and team member Charles Lackland is dispatched to the equator where he has met Barlennan by chance. Lackland is barely able to survive (machine-aided) what to the captain is the incredibly light gravity, but has managed to teach the Mesklinites English, and enlist the Bree to journey to the pole and recover the probe, in return for information about the violent weather which often plagues such expeditions. Communication is achieved through an audio-visual radio built to function in a high-gravity environment, which is treated as magical by other intelligences encountered on the planet. Along the way to the pole, the ship encounters and overcomes a variety of obstacles, some of which the humans help with using their superior scientific knowledge, and some of which rely on the cunning of Barlennan and his crew. They are captured by various lifeforms similar to themselves, but who live in the lower-gravity areas and have developed projectile weapons and gliders. Gradually, with human help, they gain an understanding of these and manage to escape. Barlennan has been dissatisfied with the humans' efforts to seemingly avoid explanation of anything scientific, and almost withholds the probe when they finally reach it; but the humans convince them that a scientific background is needed to understand the advanced equipment in the probe, and a deal is reached whereby the humans will slowly educate the Mesklinites. The novel provides an exposition on how the weather, geology and atmosphere of the seas and the pole are affected by the local conditions, and sees the Mesklinites overcoming their fear of gravity as they learn to view it scientifically, eventually harnessing aerodynamics to make the Bree fly at the poles.