(spoilers — however, most back covers also ruin the great surprise)
Hal Clement, an Oxford educated astronomer who contributed immensely to the hard-science fiction movement, is best known for his books Mission of Gravity and Needle, however Iceworld (sadly neglected) is also a very good effort.
Iceworld is about a tentacled alien named Sallman Ken, a science school teacher, who is employed by a narcotics agent to go investigate a powerful drug (you find out what the drug is in the first few pages but it is a wonderfully funny surprise).
He is hired by the drug runners who need his scientific expertise and they travel to a planet that is immensely cold, so cold for the sulfur breathing aliens that most of their technology breaks when sent to the surface. This is the very first twist (sadly, the back cover spoils it for the reader).
The aliens set up a facility on Mercury (still not hot enough for them) and send probes to Earth which pick up the drug. The aliens wish to grow the drug themselves to bypass dealing with the natives (the secondary characters in the novel) and it is up to Sallman Ken to laboriously figure out what type of atmosphere, soil content, all while snooping around for information for his boss.
The hard-science, for which Clement is so famous, involves the ways that Sallman Ken uses to learn about the Planet Earth. This is sometimes a little laborious but it instills in the reader great realism. Hal Clement is also very good at description and his “pastoral scenes” are reminiscent of Simak at his best. There is however, a big flaw: The aliens from Sarr act almost exactly like humans (despite living in massively different environments) and how they sit and the fact they have tentacles is the only thing that differentiates them from the humans for the first half of the book.
The events unfold neatly and unforced which also adds to the realism despite slightly comical premise. There are plenty of laughs (the aliens trade platinum and gold for the drug) and although the characters are relatively flat (this is 1953 science fiction) Clement obviously molds Ken after himself and tries to make others have slightly hidden backgrounds and motives.
This is a FUN book which deserves a greater audience. Definitely worthwhile for those who want to read the first generation of hard-science fiction!