Born in Bydgoszcz, Rejewski was a fellow of Poznan University and a member of Polish military intelligence. The group he formed with Jerzy Rozycki and Henryk Zygalski broke the cipher of Enigma machine and built a working replica in the 1930s. In 1939 he created a programmable electro-mechanical decoding machine named "Bomba", the predecessor of the British "bombes" and early computers like the Colossus computer. This information has been passed to allied British and French intelligence in August 1939. The British and Americans later used information gathered by Rejewski to aid their own attempts to decipher Enigma messages. During WWII he worked in French secret service in France and later escaped to Great Britain. After the WWII he returned to Poland in 1946. He was re-united with his wife and two children. He wrote a book about his work during the breaking of Enigma. This book remains unpublished.
Polish Mathematical Society has honoured him with a special medal edited especially for him.
Enigma, by Wladyslaw Kozaczuk (about history of Enigma codebreaking effort)
Machine Cryptography, by Cipher Devours and Louis Kruh (has an interview with Rejewski)