... At the end of the 20th century, the lower price of computer equipment, along with an increased capacity of processing and storage components, not to mention big data and new algorithms, set the stage for a grand era in the first decade of this millennium, with the appearance of a wide variety of free software for science mapping analysis ( Cobo et al., 2011a). Among many other achievements, science mapping become the keystone of visualizing and analyzing computer graphics ( Chen et al., 2001), using ISI categories to represent science ( Moya-Anegón et al., 2004), mapping the backbone of science ( Boyack et al., 2005), evaluating large maps of disciplines ( Klavans and Boyack, 2006), visualizing the citation impact of scientific journals ( Leydesdorff, 2007a), mapping interdisciplinarity ( Leydesdorff, 2007b), viewing the marrow of science ( Moya-Anegón et al., 2007b), creating dynamic animations of journal maps ( Leydesdorff and Schank, 2008), mapping the structure and evolution of chemistry research ( Boyack et al., 2009), proposing a consensus map of science ( Klavans and Boyack, 2009), creating a journal map using Scopus data ( ), mapping the geography of science ( Leydesdorff and Persson, 2010), clustering over two million biomedical publications ( Boyack et al., 2011), creating more accurate document-level maps of research fields ( Klavans and Boyack, 2011), detecting and visualizing the evolution of the fuzzy sets theory field ( Cobo et al., 2011b), proposing a new global science map ( Leydesdorff et al., 2013a,b;Boyack and Klavans, 2014), analyzing the investigation in integrative and complementary medicine ( Moral-Muñoz et al., 2014), analyzing intelligent transportation systems ( Cobo et al., 2014), showing the evolution of bases knowledge systems ( Cobo et al., 2015), showing the scientific evolution of social work ( Martínez et al., 2015), outlining animal science research ( Rodriguez-Ledesma et al., 2015), studying the conceptual evolution of marketing research ( Murgado-Armenteros et al., 2015) identifying and depicting the intellectual structure and research fronts in nanoscience and nanotechnology in the world ( Muñoz-Écija et al., 2017), and exploring the scientific evolution of e-Government ( Alcaide-Muñoz et al., in press), among other brave new initiatives. The proposal by Leydesdorff and Rafols (2009) of creating overlay maps can be seen as a powerful contribution integrating visualization, intellectual structure, evolution, and benchmarking, for any kind of scientific domain. ...