The last book XIII of Euclid's Elements deals with the regular solids
which therefore are sometimes considered as crown of classical geometry.
More than two thousand years later around 1850 Schl fli extended the
classification of regular solids to four and more dimensions. A few
decades later, thanks to the invention of group and invariant theory the
old three- dimensional regular solid were involved in the development of
new mathematical ideas: F. Klein (Lectures on the Icosa- hedron and the
Resolution of Equations of Degree Five, 1884) emphasized the relation of
the regular solids to the finite rotation groups. He introduced complex
coordinates and by means of invariant theory associated polynomial
equations with these groups. These equations in turn describe isolated
singularities of complex surfaces. The structure of the singularities is
investigated by methods of commutative algebra, algebraic and complex
analytic geometry, differential and algebraic topology. A paper by DuVal
from 1934 (see the References), in which resolutions play an important
rele, marked an early stage of these investigations. Around 1970 Klein's
polynomials were again related to new mathematical ideas: V. I. Arnold
established a hierarchy of critical points of functions in several
variables according to growing com- plexity. In this hierarchy Kleinls
polynomials describe the "simple" critical points.