Artificial neural networks have a major technological potential. Meanwhile, many open source machine learning software libraries exist in order to experiment with deep artificial neural networks, i.e. TensorFlow or Torch. In his presentation “Machine Learning mit künstlichen neuronalen Netzwerken in Clojure” (“Machine Learning with Artificial Neural Networks in Clojure”), Stefan Richter shows us - during the fourth code.talks in 2014 - how exciting it is to build one’s own library for artificial neural networks in Clojure.