With this Special Issue "The Periodic System, a history of shaping and sharing" edited by Brigitte Van Tiggelen, Annette Lykknes, Luis Moreno-Martinez, Substantia contributes to the celebrations of the 150^th anniversary of the periodic table.

Cover image: Polarized Light micrograph (magnification 45x) from scopoletin heated with chloroform and acetic acid, by Lars Bech, Naarden, The Netherlands. Courtesy of Nikon Small World (14^th Place, 2000 Photomicrography Competition, https://www.nikonsmallworld.com).