  We describe a conjecture on the algebra of higher cohomology operations which
leads to the computations of the differentials in the Adams spectral sequence.
For this we introduce the notion of an n-th order track category which is
suitable to study higher order Toda brackets and the differentials in spectral
sequences. We describe various examples of higher order track categories which
are topological, in particular the track category of higher cohomology
operations. Also differential algebras give rise to higher order track
categories.
