The Drell-Hearn-Gerasimov sum-rule is really two sum-rules: one for ea
ch of the valence and the sea/glue contributions to the nucleon wavefu
nction. The convergence of these sum-rules follows from the Froissart
bound for spin dependent processes in QCD and is necessary for the con
sistency of the constituent quark model of low energy QCD. Some challe
nges for future polarised photoproduction experiments, for example at
ELFE, are discussed.