The 4th IEEE International Conference on Data Science in Cyberspace (IEEE DSC) will be held in Hangzhou, China, June 23-25, 2019. Over the past three years, IEEE DSC has become one of the most important and attractive international conference, mainly focusing on data science and its application in cyberspace. The conference will feature world-class speakers, workshops, demonstrations, exhibits, and innovative programs. Data Science, as a highly interdisciplinary field, is playing a more and more critical and central role in the development of cyberspace and various applications. Data science in cyberspace is an integral part of competitive intelligence, a newly emerging field that encompasses a number of activities, such as data mining and data analysis. Data science in cyberspace inspires novel techniques and theories drawn from many areas, such as mathematics, statistics, information theory, computer science, and social science, and involves many specific domains, such as signal processing, probability models, machine learning, statistical learning, data mining, database, data engineering, pattern recognition and learning, visualization, predictive analytics, uncertainty modeling, data warehousing, data compression, computer programming, and high performance computing.