[en] Measurements were made of the proton and deuteron spin structure functions g₁^p and g₁^d at beam energies of 29.1, 16.2, and 9.7 GeV, and g₂^p and g₂^d at a beam energy of 29.1 GeV. The integrals Λ_p = ∫₀¹ g₁^p (x, Q²)dx and Λ_d = ∫₀¹ g₁^d(x, Q²)dx were evaluated at fixed Q² = 3 (GeV/c)² using the 29.1 GeV data to yield Λ_p = 0.127 ± 0.004(stat.) ± 0.010(syst.) and Λ_d = 0.041 ± 0.003 ± 0.004. The Q² dependence of the ratio g₁/F₁ was studied and found to be small for Q² > 1 (GeV/c)². Within experimental precision the g₂ data are well-described by the twist-2 contribution, g₂^WW. Twist-3 matrix elements were extracted and compared to theoretical predictions. The asymmetry A₂ was measured and found to be significantly smaller than the positivity limit √R for both proton and deuteron targets. A₂^p is found to be positive and inconsistent with zero