In the 19 years which passed since the first edition was published,
several important developments have taken place in the theory of
surfaces. The most sensational one concerns the differentiable structure
of surfaces. Twenty years ago very little was known about differentiable
structures on 4-manifolds, but in the meantime Donaldson on the one hand
and Seiberg and Witten on the other hand, have found, inspired by gauge
theory, totally new invariants. Strikingly, together with the theory
explained in this book these invariants yield a wealth of new results
about the differentiable structure of algebraic surfaces. Other
developments include the systematic use of nef-divisors (in ac- cordance
with the progress made in the classification of higher dimensional
algebraic varieties), a better understanding of Kahler structures on
surfaces, and Reider's new approach to adjoint mappings. All these
developments have been incorporated in the present edition, though the
Donaldson and Seiberg-Witten theory only by way of examples. Of course
we use the opportunity to correct some minor mistakes, which we ether
have discovered ourselves or which were communicated to us by careful
readers to whom we are much obliged.