This book gathers the best papers from the HKAECT-AECT 2017 Summer International Research Symposium. Revealing the complex interactions between communication and learning, which are represented by the symbol "X" in the title, it provides a platform for knowledge exchange on the new ecology for education in the digital era. It also equips readers to handle complex issues in both communication and education, and clarifies the difference between practitioners and academics in communication and in education.