This book constitutes the extended and revised versions of a set of selected papers from the 13th International Joint Conference on Knowledge Discovery, Knowledge Engineering and Knowledge Management, IC3K 2021, on October 25-27, 2021. The conference was held virtually due to the COVID-19 crisis. The 9 full papers included in this book were carefully reviewed and selected from 103 submissions. The purpose of the IC3K is to bring together researchers, engineers and practitioners on the areas of Knowledge Discovery, Knowledge Engineering and Knowledge Management. IC3K is composed of three co-located conferences, each specialized in at least one of the aforementioned main knowledge areas.