A synthetic approach to intrinsic differential geometry in the large and
its connections with the foundations of geometry was presented in "The
Geometry of Geodesics" (1955, quoted as G). It is the purpose of the
present report to bring this theory up to date. Many of the later
ip.vestigations were stimulated by problems posed in G, others concern
newtopics. Naturally references to G are frequent. However, large parts,
in particular Chapters I and III as weIl as several individual seetions,
use only the basic definitions. These are repeated here, sometimes in a
slightly different form, so as to apply to more general situations. In
many cases a quoted result is quite familiar in Riemannian Geometry and
consulting G will not be found necessary. There are two exceptions: The
theory of paralleIs is used in Sections 13, 15 and 17 without
reformulating all definitions and properties (of co-rays and limit
spheres). Secondly, many items from the literature in G (pp. 409-412)
are used here and it seemed superfluous to include them in the present
list of references (pp. 106-110). The quotations are distinguished by [
] and ( ), so that, for example, FreudenthaI [1] and (I) are found,
respectively, in G and here.