Kaj Sand-Jensen is a Professor in Freshwater Ecology at the University of Copenhagen, and former Professor in General Plant Ecology and Physiology at the University of Aarhus, Denmark. He is the author of many scientific articles and books on cyanobacteria, algae and plants, as well as books on ecology, biodiversity, and conservation. He is a member of the Danish Natural Science Academy and the Royal Danish Scientific Society.Jens Christian Schou is a retired teacher and a photographer and illustrator of plants, animals, and landscapes, based in Denmark. He has authored and illustrated numerous botanical works on the identification and biology of plants including sedges, brambles, hawkweeds, umbellifers, grasses, and aquatic plants. He is the first author of Aquatic Plants of Northern and Central Europe including Britain and Ireland, and was an artist for the multi-volume series Flora of Ecuador.David Barden received undergraduate and PhD degrees in Natural Sciences(Chemistry) from Cambridge University before working as a technical editor for Wiley VCH and the Royal Society of Chemistry, and then as a technical/marketing copywriter. Now based near Cardiff, he is a freelance writer and editor with a focus on science and technology. David has a long interest in botany and plant identification and is a member of the Botanical Society of Britain & Ireland, for which he has been vice-county recorder for Glamorgan since 2020.