Arthur Samuel (1959) : "Field of study that gives computers the ability to learn without being explicitly programmed“ Tom Mitchell (1998) : “A computer program is said to learn from experience E with respect to some task T and some performance measure P, if its performance on T, as measured by P, improves with experience E”. There are several ways to implement machine learning algorithms Automating automation Getting computers to program themselves Writing software is the bottleneck Let the data do the work instead!