  We discuss an universal bordism invariant obtained from the
Atiyah-Patodi-Singer eta-invariant from the analytic and homotopy theoretic
point of view. Classical invariants like the Adams e-invariant,
$\rho$-invariants and $String$-bordism invariants are derived as special cases.
The main results are a secondary index theorem about the coincidence of the
analytic and topological constructions and intrinsic expressions for the
bordism invariants.
