  This thesis considers various aspects of locally covariant quantum field
theory (LCQFT; see Brunetti et al., Commun.Math.Phys. 237 (2003), 31-68), a
mathematical framework to describe axiomatic quantum field theories in curved
spacetimes. New results include: a philosophical interpretation of certain
aspects of this framework in terms of modal logic; a proof that the truncated
n-point functions of any Hadamard state of the free real scalar field are
smooth, except for n=2; a description of he free Dirac field in a
representation independent way, showing that the theory is determined entirely
by the relations between the adjoint map, the charge conjugation map and the
Dirac operator; a proof that the relative Cauchy evolution of the free Dirac
field is related to its stress-energy-momentum tensor in the same way as for
the free real scalar field (cf. loc.cit.); several results on the
Reeh-Schlieder property in LCQFT, including but not limited to those of our
earlier paper; a new and elegant approach to wave front sets of Banach
space-valued distributions, which allows easy proofs and extensions of results
in the literature.
