When the first issue of the Data Science Journal was published by CODATA in 2002, it was perhaps the first journal dedicated to the new concept of “data science.” Since the beginning, Data Science Journal papers have advanced understanding of many aspects of the science of data, including the capture of data, their analysis, metadata, retrieval, archiving, exchange, mining to find unexpected knowledge and data relationships, and visualization, along with intellectual property rights and other legal and ethical issues related to data. Since 2002, data science has evolved significantly, becoming a topic of significant interest in academic research, public and private sector workplaces, and in government policies and practices. Data science has emerged as a panoply of techniques, tools, and skills that can be applied to derive value (economical or intellectual) out of the growing piles of data. This special collection provides reflection and discussion on the core topics within data science, past, present, and future. These contributions align with the goals of the Data Science Journal since the beginning, namely that “data science” must consider the science of data and issues of data in science.