This edited book is based on the research papers presented at the 4th International Conference on Intelligent, Interactive Systems and Applications (IISA2019), held on June 28–30, 2019 in Bangkok, Thailand. Interactive intelligent systems (IIS) are systems that interact with human beings, media or virtual agents in intelligent computing environments. This book explores how novel interactive systems can intelligently address various challenges and also limitations previously encountered by human beings using different machine learning algorithms, and analyzes recent trends. The book includes contributions from diverse areas of IIS, here categorized into seven sections, namely i) Intelligent Systems; ii) Autonomous Systems; iii) Pattern Recognition and Computer Vision; iv) E-Enabled Systems; v) Internet & Cloud Computing; vi) Mobile & Wireless Communication; and vii) Various Applications. It not only presents theoretical knowledge on the intelligent and interactive systems but also discusses various applications pertaining to different domains.