This book investigates the late Neoproterozoic N-S trending Wadi Yiba Shear Zone (WYSZ) in southern Arabian Shield. WYSZ played a significant role in the structural shaping of the basement lithologies (gneisses, metavolcanics, Ablah Group (meta-clastic and marble units) and syn- and post-tectonic granitoids) exposed in Wadi Yiba, Asir tectonic terrane. Effects of, at least, three phases of deformation are detected (D1-D3). Among these phases, D2 deformation phase was intensive and pervasive, and responsible for the formation of the WYSZ. Minor and major F2 thrust- and shear zone-related folds are coeval to this phase. The deformation patterns in the area reflect the progressive convergence between East and West Gondwanalands