"Half Mile Down" is a book by William Beebe that describes the journeys of the bathysphere. The book is the third volume to be published about oceanographic research on the waters around Nonsuch, Bermuda. In the book, Beebe writes about siphonophores that are "lovely as the finest lace" and "pteropods, or flying snails, each of which lived within a delicate, tissue shell, and flew through life with a pair of flapping, fleshy wings".

Some say that the book is an exceptional read that will motivate young explorers to pursue their dreams. Academicians and scholars have considered the book to be of great significance and value to literature.