Ten papers address both empirical and analytical aspects of clay and shale slope instability. Among the topics discussed in detail are: limit equilibrium stability analysis, shear strength of clay and clayey colluvium, use of triaxial test data to evaluate viscoplastic slope movements, numerical modeling of pore pressure distribution in heterogeneous soils, rational analysis of rainfall and landslide movement patterns, the effects of hydrothermal alteration on slope stability, mudrock durability and stability considerations, and regional clay and shale slope stability problems in Italy.