With this Special Issue "Water in biology: what’s so special about it?" edited by Marc Henry, Substantia contributes to the celebrations of the 150^th anniversary of the periodic table.

Cover image: Differential Interference Contrast micrograph (magnification 40x) from a sodium vanadate crystal, by Keith Yagaloff Ph.D., Hoffmann-La Roche, Nutley, New Jersey, USA. Courtesy of Nikon Small World (8^th Place, 1995 Photomicrography Competition, https://www.nikonsmallworld.com).