Green leather-covered boards, gilt titles (early 20th century binding?). The introduction is addressed to the authors’ grandsons, and the volume is written as a series of letters between two friends, recounting episodes that throw light on instinctive behaviour in animals, as well as some pointing up instances where the behaviour seems the result of learning or reason. Condition: Considerable foxing to some pages. After the front free end paper, contents are title page, one leaf of dedication [v], vi, then the Preface, numbered [vii] viii, ix, x, xi, xii, then the Contents up to xviii, then the text. Binding firm and sound, with just a little rubbing to the spine.