This proceedings book presents recent research work and results in the area of communication and information technologies. The chapters of this book contain the main, well-selected and reviewed contributions of scientists who met at the 12thInternational Conference on Computing and Information Technology (IC2IT) held during 7th - 8th July 2016 in Khon Kaen, Thailand The book is divided into three parts: "User Centric Data Mining and Text Processing",  "Data Mining Algoritms and their Applications" and "Optimization of Complex Networks".