This book gathers a collection of high-quality peer-reviewed research papers presented at International Conference on Computational Techniques and Applications (ICCTA 2021), organized by the Electronics and Telecommunication Engineers (IETE), Kolkata Center, India, during 8 - 9 October 2021. This includes research in the areas of intelligent computing and communication systems including computing, electronics, green energy design, communications, computers to interact and disseminate information on latest developments both academically and industrially for computational drifts. The three main tracks are (i) computing in network security, AI and data science; (ii) contemporary issues in electronics, and communication technology; and (iii) intelligent computing in electrical power, control systems and energy technology.