The magnetic properties of silicates and phosphates are compiled in subvolume 27I. While subvolumes 27I1, 27I2 and 27I3 (already published) deal with orthosilicates, sorosilicates and cyclosilicates, respectively, . the present subvolume 27I4 deals with inosilicates. Further subvolumes are dedicated to other types of silicates (phyllosilicates, tectosilicates) and to phosphates. - Silicates are very complex systems, covering large classes of minerals...