It is with great sadness that we let you know that John Holland, one of the founders of Artificial Intelligence and Complex System Science, passed away Sunday morning, 8 August 2015 in Ann Arbor Michigan, USA. John was a great original thinker who formulated and studied complex adaptive systems, was the inventor of Genetic Algorithms, Classifier Systems and Echo models. The world and especially the computer science society owes a lot to John. Here is one of the last recorded informal lectures/session (21 February 2015, NTU, Singapore) with John Holland moderated by Peter Sloot and with an inspiring introduction by Brian W. Arthur. See: http://youtu.be/a_u_d-KLEsE