To date, researchers have identified more than 10,000 encrypted messages spanning the last five centuries. Deciphering these messages is an active area of research. Two powerful algorithmic approaches have proven especially useful in cracking historical ciphers: Hill Climbing and Simulated Annealing. In this talk, Klaus Schmeh, co-author of Codebreaking: A Practical Guide, will explain how Hill Climbing and Simulated Annealing work and share a variety of real-world examples.