This book constitutes the refereed proceedings of the 6th International Conference,on Theory and Practice of Natural Computing, TPNC 2017, held in Prague, Czech Republic, December 2017.The 22 full papers presented in this book, together with one invited talk, werecarefully reviewed and selected from 39 submissions.

This book constitutes the proceedings of the 5th InternationalConference on Algorithms for Computational Biology, AlCoB 2018, held in Hong Kong, China, in June 2018. The 11 full papers presented together with 1 invited paper were carefully reviewed and selected from 20 submissions.