GIDEON SMITH is Chief Director: Biosystematics Research and Biodiversity Collections at the SA National Biodiversity Institute. He is involved in various national and international environmental associations and advisory committees. His interests are in the biology and classification of succulent plants, as well as landscaping and horticulture. South Africa's most prolific author on succulent plants, he has authored or co-authored 40 books, and more than 500 research and popular papers, mostly on succulents. Braam van Wyk is a member of the lecturing staff at the University of Pretoria, where he is a professor in the Department of Plant Science. He did his tertiary training at the Potchefstroom University for Christian Higher Education and the University of Pretoria. Braam is a plant taxonomist and has authored or co-authored numerous publications on the botany of southern Africa, including several books. Among his published works are Field Guide to the Wild Flowers of the Highveld (Struik, 1997), How to Identify Trees in Southern Africa (Struik, 2007) and Field Guide to Trees of Southern Africa (Struik, 2013).