This book is a natural history about animals, plants and human beings. While depicting animals, Buffon, with warm affections, portrays them with the personification gimmick and makes the vivid images stand out markedly, such as the kind and lovely squirrel, the gentle and honest elephant, and the loving doves; while studying on the origin of species, Buffon advocates the 'biotransformation theory' and points out that the external factors such as environment, climate and food can lead to biomutation; the view directly affects the subsequent Theory of Evolution. Buffon lists numerous facts and materials, makes precise, detailed and scientific description and interpretation to the nature, and puts forward many valuable insights in the book.