Hal Clement

The Nitrogen Fix is a 1980 science fiction novel by Hal Clement. The plot revolves around a nomadic family in a future where all oxygen in the Earth's atmosphere has combined with nitrogen, so the atmosphere is mostly nitrogen with traces of water, nitrogen oxides and carbon dioxide, and the seas are very dilute …

Time was running out for Bob Kinnaird. Without much warning, the Hunter - the green protoplasmic alien that lived inside him and cured all his ills - had suddenly become his destroyer. Day by day Bob grew weaker and weaker, but only specialists from the Hunter's distant world would know what was wrong with him and, …

Close to Critical is a science fiction novel by Hal Clement. The novel was first serialized in three parts and published in Astounding Science Fiction magazine in 1958. Its first hardcover book publication was in July 1964.