The authors have long felt the need for a treatise on the principles and
methods of taxonomy. Such a work should be useful not only as an
adjunct to teaching but also as a reference work for the practicing
taxonomist and as a source of information to the general biologist. An
analysis and full statement of the often disputed principles on which the
taxonomic method is based are urgently needed. We share the view of
O. W. Richards (1947) that "it is less the findings of taxonomy than its
principles and methods which need to be taught" and understood. We
believe that taxonomy is an important branch of biology which deals not
only with the identification and classification of natural populations but
with objectives that go well beyond these fundamental activities. [...]

In attempting to bring together the more important elements of
modern taxonomic theory and practice, we have, of necessity, selected
our materials primarily from the point of view of the student of living
animals and have chosen illustrative examples with preference from our
mvn work. The problems of the paleontologist, microbiologist, and
botanist have been taken into consideration as far as practicable, but the
materials of these groups are often sufficiently different to require different
approaches to the solution of taxonomic problems. Nevertheless, there
is much common ground of theory and method shared by the workers in
these diverse fields, and it is to be hoped that at some time in the not too
distant future all biological taxonomy may be viewed· as a single cohesive
field. If this book, by focusing attention on the problems of the systematic
zoologist, serves as a step in that direction, one of its goals will have
been achieved. If it also assists in stimulating a more critical evaluation
of taxonomic theory and methods and in a wider dissemination of knowledge
concerning them, the authors will feel that their labors have been
justified. [From the Preface]