Algorithms are the hidden methods that computers apply to process information and make decisions. The book tells the story of algorithms from their ancient origins to the present day and beyond. The book introduces readers to the inventors and events behind the genesis of the world’s most important algorithms. Along the way, it explains, with the aid of examples and illustrations, how the most influential algorithms work. The first algorithms were invented in Mesopotamia 4,000 years ago. The ancient Greeks refined the concept, creating algorithms for finding prime numbers and enumerating Pi. Al-Khawrzmi’s 9th century books on algorithms ultimately became their conduit to the West. The invention of the electronic computer during World War II transformed the importance of the algorithm. The first computer algorithms were for military applications. In peacetime, researchers turned to grander challenges - forecasting the weather, route navigation, choosing marriage partners, and creating artificial intelligences. The success of the Internet in the 70s depended on algorithms for transporting data and correcting errors. A clever algorithm for ranking websites was the spark that ignited Google. Recommender algorithms boosted sales at Amazon and Netflix, while the EdgeRank algorithm drove Facebook’s NewsFeed. In the 21st century, an algorithm that mimics the operation of the human brain was revisited with the latest computer technology. Suddenly, algorithms attained human-level accuracy in object and speech recognition. An algloirthm defeated the world champion at Go - the most complex of board games. Today, algorithms for cryptocurrencies and quantum computing look set to change the world.