This book constitutes the refereed proceedings of the 4th
International Conference on Theory and Practice of Natural Computing, TPNC
2015, held in Mieres, Spain, in December 2015.



The 12 revised full papers presented together
with 20 invited talks in this book were carefully reviewed and selected from 30
submissions. The scope of TPNC is rather broad, containing topics of either
theoretical, experimental or applied interest such as soft computing, computing
architectures, and formal models.