This is a revised and enlarged edition of C. V. Boys' Christmas Lectures delivered at the Royal Institution in 1889 on the subject of soap bubbles. The deceptive simplicity of the title disguises the complicated phenomena it represents, ranging from a scientific discussion of liquids to the numerous experiments performed with the simple soap bubble. The original illustrations and diagrams have been redrawn and a new introduction and a brief biography of Boys added. Bubble blowing amateurs beware. This is strictly for the science buff.