This monograph is based on the work of the author on surface theory con-
nected with ball uniformizations and arithmetic ball lattices during
several years appearing in a lot of special articles. The first four
chapters present the heart of this work in a self-contained manner (up
to well-known ba- sic facts) increased by the new functorial concept of
orbital heights living on orbital surfaces. It is extended in chapter 6
to an explicit HURWITZ theory for CHERN numbers of complex algebraic
surfaces with the mildest singularities, which are necessary for general
application and proofs. The chapter 5 is dedicated to the application of
results in earlier chapters to rough and fine classifications of PICARD
modular surfaces. For this part we need additionally the arithmetic work
of FEUSTEL whose final results are presented without proofs but with
complete references. We had help- ful connections with Russian
mathematicians around VENKOV, VINBERG, MANIN, SHAFAREVICH and the nice
guide line of investigations of HILBERT modular surfaces started by
HIRZEBRUCH in Bonn. More recently, we can refer to the independent
(until now) study of Zeta functions of PICARD modular surfaces in the
book [L-R] edited by LANGLANDS and RAMAKR- ISHN AN. The basic idea of
introducing arrangements on surfaces comes from the monograph [BHH],
(BARTHEL, HOFER, HIRZEBRUCH) where linear ar- rangements on the complex
projective plane ]p2 play the main role.