This is a difficult book on account of the very wide range and complexity of its subject-matter, made more difficult by the fact that the author has not taken the trouble to arrange his writing so as to present a clear sequence of ideas; also he often uses needlessly complex sentences, some made more difficult to understand by careless proof-reading. After a first attempt to read the book through, my mind was quite confused; it was only on a second reading, by referring backwards and forwards to different chapters, that I began to have some understanding of its basic ideas. So if in this review I do not do it justice, I feel that the author will be at least in part to blame. Prof. Meeuse has made an attempt to interpret the floral morphology of flowering plants in terms of a new typology. Fie objects to the old typology of carpels and the way in which a great range of different floral structures were interpreted in terms of that typology; but he proceeds to provide a new strait-jacket of his own into which all the same structures must be fitted. He condemns the old morphology as ‘preconceived’, and frequently uses this adjective to discredit the ideas of others. But all his own theoretical ideas must have been conceived in his own mind before he could apply them in detail and give expression to them in the present book; they are therefore also pre-conceived. He should think again what he means by this word.