This dissertation presents results of experiment E94-010 performed at Jefferson Laboratory (simply known as JLab) in Hall A. The experiment aimed to measure the low Q{sup 2} evolution of the Gerasimov-Drell-Hearn (GDH) integral from Q{sup 2} = 0.1 to 0.9 GeV{sup 2}. The GDH sum rule at the real photon point provides an important test of Quantum Chromodynamics (QCD). The low Q{sup 2} evolution of the GDH integral contests various resonance models, Chiral Perturbation Theory ({chi}#31;PT) and lattice QCD calculations, but more importantly, it helps us understand the transition between partonic and hadronic degrees of freedom. At high Q{sup 2}, beyond 1 GeV{sup 2}, the difference of the GDH integrals for the proton and the neutron is related to the Bjorken sum rule, another fundamental test of QCD. In addition, results of the measurements for the spin structure functions g{sub 1} and g{sub 2}, cross sections, and asymmetries are presented. E94-010 was the first experiment of its kind at JLab. It used a high-pressure, polarized {sup 3}He target with a gas pressure of 10 atm and average target polarization of 35%. For the first time, the polarized electron source delivered an average beam polarization of 70% with a beam current …