Every year thousands of people are killed by bacteria that have grown resistant to antibiotics. New alternatives are urgently needed. A surprising ray of hope is actually a blast from the past. Viruses that kill bacteria, but not us, called 'phages' for short were discovered around 1915, when infections were still a major cause of illness and death. Phage therapy became popular from the 1920s until the introduction of penicillin 20 years later. Only in the countries of the Eastern block did the therapy survive and thrive. Now western researchers and companies are working on a comeback for phage therapy. This book tells the fascinating story of the discoverers of phages in the west and the Soviet Union. Award-winning science journalist Thomas Hausler follows the trail of one pioneer killed by Stalin's secret service, and his successors in today's war-torn Georgia, accompanies patients taking phages because standard drugs fail them and investigates how these long-forgotten cures may help sick people today.