...[T]here are few indeed except trained naturalists who realize that
any but a quite casual and superficial relation exists between these
woodland toadstools and the trees under which they appear, or have
carried their observations a stage further and noted the regular
coincidence of certain kinds with particular tree species. The
association between the toadstool-producing fungi of woodlands and our
common trees is only one of many unlikely ways in which plants belonging
to widely different groups are interrelated with one another and with
the mechanism of life as a whole. Because this is so, and because there
is a widespread and somewhat surprising lack of curiosity about the
jigsaw puzzle formed by the different kinds of life that surround us in
nature; about the interplay and interdependence of their various vital
activities and the pattern formed when these are fitted together... it
has seemed worth while to write this little book. (From the
Introduction)