Hal Clement was the pseudonym of American high school teacher Harry Stubbs. Hal Clement wrote hard SF: the purest hard SF I have ever read, because his novels depend on the application of fundamental principles of physics and chemistry, as known during his heyday in the early 1950s.
Hal Clement writes about decent men (I use the term advisedly) working together decently to solve difficult problems. Some of the “men” are aliens, and part of the difficulty usually arises from the physical differences between the humans and the aliens. In Mission of Gravity, Clement’s most famous novel, the inhabitants of the planet Mesklin are fifteen-inch-long, caterpillar-like creatures whose planet varies in gravity from 3x Earth’s gravity at the equator to 800x at the poles. The human explorers need the Mesklinites’ help to recover a valuable spaceship from the poles, and the driver of the story is the differing chemistry and physics that apply as the trading ship Bree makes its way across stormy methane seas from equator to Pole.
Sounds dull? It’s not – it’s fascinating. Though these are not exactly novels of character, the relationship between human explorer Charles Lackland and the captain of the Bree, Barlennan, is by turns moving, amusing and exciting. Although the dialogue sometimes betrays the age of the book – “Dave, put down that slide rule and get to a calculator” – the simplicity of the storyline, and the complexity of the setting, render such anachronisms irrelevant.
In Iceworld, the boot is on the other foot: literally, for here an undercover agent from a planet whose inhabitants breathe gaseous sulphur must somehow work together with the bizarre inhabitants of the incomparably cold, bleak, and seemingly uninhabitable Earth to stop the trade in a deadly drug. (Others of Clement’s novels, such as Needle, use a similar intergalactic-crime plot armature.) The book is told from the alternating perspectives of the sulphur-beating Sallman Ken and the human Wing family. Each starts with wildly incorrect assumptions about the other, and the process of learning to communicate drives the plot, as it does to a lesser extent in Mission of Gravity.
Iceworld has some structural problems: the Wing family disappears for a large portion of the novel, as the narrative focuses on Sallman Ken’s efforts to make a spacesuit capable of withstanding the hideous cold of Earth. But it doesn’t really matter, because the pleasures of Iceworld lie in the triumph of reason over unreason, cooperative effort over selfishness. Chemistry, physics, and decency: three good reasons to read Hal Clement.