  Starting with topological field theories we investigate the Ray-Singer
analytic torsion in three dimensions. For the lens Spaces L(p;q) an explicit
analytic continuation of the appropriate zeta functions is contructed and
implemented. Among the results obtained are closed formulae for the individual
determinants involved, the large $p$ behaviour of the determinants and the
torsion, as well as an infinite set of distinct formulae for zeta(3): the
ordinary Riemann zeta function evaluated at s=3.
  The torsion turns out to be trivial for the cases L(6,1), L((10,3) and
L(12,5) and is, in general, greater than unity for large p and less than unity
for a finite number of p and q.
