2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/38981Comments on the recent lattice QCD calculations of the flavor-singlet axial coupling constant $g_A^0$ and individual quark and gluon spin contributions to the proton spin is given. I point out the physics learned from these calculations as well as some of the lessons and pitfalls.11-page Latex file, no figures, Report for the workshop on ``Future Physics at HERA'', Sept. 25 - 26, 1995High Energy Physics - LatticeHigh Energy Physics - Phenomenologytext