The last few years have seen a number of new books on evolutionary
biology. However most of these are either large or specialized. This is
an attempt to produce a thin, general version for undergraduate use.
Thinness, of course, demands selectivity, and the aim has been to
concentrate on the principles of the subject rather than on the
details-principles, that is, of both theory and practice. Thinness also
sometimes means that a certain level of knowledge is assumed in the
readership, but I hope that this is not the case here, and my intention
has certainly been to produce something that is as intelligible to the
uninitiated as it is to the well-informed. As for the bibliography, I
refer, where possible, to reviews rather than primary sources, so a
citation should not be taken to imply any sort of precedence. In
developing the theme, I have adopted a loosely historical approach, not
only because I believe that this makes for more interesting reading but
also because the subject, like the subject it addresses, has evolved
under the critical eye of a selective process. Problems have been
perceived, hypotheses have been formulated to explain them, facts have
been amassed to test the hypotheses, more problems have been perceived,
more hypotheses formu- lated, and so on.