2023 Reprint of the 1927 edition. Here is the true story of the adventures of explorers in the fantastic world of the unseen. These explorers were like other men; they had curiosity; they groped, sometimes failed. They found truth, they fought death; a few were caught in ambush by the invisible assassins they were trying to trap. They were the pioneers in the struggle of mankind to conquer its worst enemies.

An international bestseller, translated into eighteen languages, Paul de Kruif's classic account of the first scientists to see and learn about the microscopic world continues to fascinate new readers. This is a timeless dramatization of the scientists, bacteriologists, doctors, and medical technicians who discovered the microbes and invented the vaccines to counter them. De Kruif writes about how seemingly simple but really fundamental discovers of science-for instance, how a microbe was first viewed in a clear drop of rain water, and when, for the first time, Louis Pasteur discovered that a simple vaccine could save a man from the ravages of rabies by attacking the microbes that cause it.

Contents: Leeuwenhoek -- Spalianzani -- Pasteur -- Koch -- Roux and Behring -- Metchnikoff -- Theobald Smith -- Bruce -- Ross vs. Grassi -- Walter Reed -- Paul Ehrlich.