Volume 19 of Group III (Crystal and Solid State Physics) deals with magnetic properties of metals, alloys and metallic compounds. The amount of information available in this field is so substantial that several sub- volumes are needed to cover it all. Subvolumes III/19a through III/19f treat the intrinsic magnetic properties, i.e. those magnetic properties which depend only on the chemical composition and the crystal structure. So far, subvolumes III/19a, III/19b, III/19c, III/19d2, III/19e1 and III/19e2 have appeared. The present subvolume III/19d1 is concerned with rare earth elements, their hydrides, and alloys between rare earth elements. Subvolume III/19f where data of actinide elements are compiled and which also contains an index of substances for subvolumes III/19a...f, is due in the near future. Data on the properties that depend on the preparation of the samples measured, as for instance, thin films or liquid-quenched alloys have been published in subvolumes III/19g and III/19h. The magnetic alloys used in technical applications (soft and hard magnetic alloys, Invar and Elinvar alloys) will be dealt with in subvolume III/19i, the last of the subvolumes of III/19.