Book excerpt: A practical guide to using gouache in botanical painting, by a leading botanical painter. Gouache is an opaque water-based medium, often called body colour, that produces crisp and vibrant paintings, and is becoming increasingly popular in botanical painting. Leading botanical painter, Simon Williams, specializes in painting in gouache and this is his first book. Botanical Painting in Gouache is full of practical advice on all aspects of using the exciting medium of gouache and contains many step-by-step demonstration paintings. In addition to the sumptuous flower paintings there are also sections on painting butterflies, birds and exotic and unusual plants from the rainforest.