Explore the intricacies of proton spin structure in this 57-minute lecture by Christine Aidala, part of the International School and Workshop on Probing Hadron Structure at the Electron-Ion Collider. Delve into the potential of the upcoming Electron-Ion Collider (EIC) at Brookhaven National Lab to revolutionize our understanding of proton and neutron internal structures. Learn how the EIC will investigate key questions about quark and gluon distribution, mass generation in visible matter, proton spin composition, and gluon saturation in heavy ion collisions. Gain insights into the EIC's high luminosity and wide kinematical coverage, which will provide unprecedented access to new information about nucleon structure. This talk is part of a comprehensive program featuring both a school for students and early-career researchers and a workshop for discussing frontier areas in EIC physics.