  Modifying a method of Jutila, we prove a t aspect subconvexity estimate for
L-functions associated to primitive holomorphic cusp forms of arbitrary level
that is of comparable strength to Good's bound for the full modular group, thus
resolving a problem that has been open for 35 years. A key innovation in our
proof is a general form of Voronoi summation that applies to all fractions,
even when the level is not squarefree.
