  The limited statistics of the available (anti)neutrino-hydrogen interactions
has been a longstanding impediment for neutrino physics. We propose a practical
way to achieve accurate (anti)neutrino-hydrogen measurements, solving the
principal limitations of earlier experiments. Interactions on hydrogen are
extracted by subtracting measurements on thin dedicated graphite (pure C) and
polypropylene (CH$_2$) targets within a highly segmented low-density detector.
A statistics of ${\cal O}(10^6)$ can be realistically achieved for the various
$\nu(\bar \nu)$-H event topologies, with efficiencies exceeding 90\% and
purities around 80-95\%. The availability of such samples allows a
determination of neutrino and antineutrino fluxes with precisions better than
1\% using conventional wide-band beams. Furthermore, by contrasting these
samples to corresponding measurements on heavy materials, initial and final
state nuclear effects can be directly constrained in a model-independent way.
The systematic uncertainties associated with both the fluxes and the nuclear
smearing are crucial for long-baseline neutrino oscillation experiments.
(Anti)neutrino-hydrogen interactions also provide an ideal tool for a wide
range of precision tests of fundamental interactions.
