Two men who build an experimental excavating vehicle discover it cannot be turned, and it burrows 500 miles into the Earth's crust, emerging into the unknown interior world of Pellucidar.
The way we feel about another person, or about objects, is often bound up in associations that have no direct connection with the person or object at all.
The Solar Queen and her crew have the trading rights to the wealthy planet Sargol, but to take advantage of them and see any return on their investment they must fight the Reptilian Gorp, negotiate with the cat-like Salariki, and find a cure for the sleeping sickness that has caused the Solar Queen to be called a plague ship and which has other ships looking to destroy them on sight.
The paper had gone to press, graphically describing the latest of the many horrible events which had been enacted upon the Earth in the last six months.