With its scientific detail, with its neatly systematized new little world, and with its crafty interpretation of both the baser and finer instincts of mankind, this funny sequel to The Wonderful Flight to the Mushroom Planet will delight anyone who isn't like Horatio, the stowaway. Chuck and David, the two boys who met Dr. Tyco Bass, the spore man from Basidium who was living on Earth, have been left in charge of his wonderful little laboratory in California after Dr. Bass requested them to start a science club and then ""blew away"". Their decision to ask a famous astronomer to come to speak to the club coincides with the arrival of Theodosius Bass, Tyco's cousin. Then, the astronomer's assistant, brash young Horatio, intercepts the boys' letter and having already heard mysterious things about Tyco's work, decides to go himself and see what he can find out. His nosiness proves fruitful. Theodosius and the boys (who are under a pledge of secrecy lest small, misty Basidium be invaded by large, forceful humans, who would spoil things) have decided to go to the planet and Horatio, bespectacled and armed with a notebook, smuggled himself aboard their space ship for a journey he is sure will bring him fame. How Horatio's pride suffers writes an amusing finis to this second fascinating encounter with the mushroom people.