Deep learning is machine learning where the system develops ("learns") its own featureset. Generally by a multilayer neural network. Selecting features is typic

Deep learning is machine learning where the system develops ("learns") its own featureset. Generally by a multilayer neural network. Selecting features is typically the aspect of machine learning that required the most domain experience, and in deep learning that part is done by an algorithm. The features can be layered. For example, speech recognition could have layers something like phonemes, morphemes, words, concepts, etc. building such featursets by hand is challenging, in deep learning the system learns useful features by detecting patterns. Interesting that the most challenging technical task is among the first to be replaced by an algorithm ;)