Nickel is probably the most versatile of the metallic elements. Among alloys containing nickel are some having high corrosion resistance and others that retain excellent strength and ductility from temperatures approaching ab­ solute zero to those near 2000 F. Some nickel alloys are strongly magnetic, others are virtually nonmagnetic; some have low rates of thermal expansion, others have high rates; some have high electrical resistivities; some have practically constant moduli of elasticity; one has an "elastic" memory. In addition, nickel is magnetostrictive. With this wide range of characteristics, it is not surprising that there are several thousand alloys containing nickel. It is impossible to consider all of these compositions in this publication and, therefore, several alloys in each of a number of categories have been selected to indicate the properties to be expected of the group. Low-alloy and constructional nickel-containing steels have been excluded on two grounds. To do them justice would require excessive space and, in addition, their applications differ generally from these of the materials under discussion. On the other hand, nickel-containing stainkss steels have been included because many of their applications fall into the same areas as those of a number of the high-nickel alloys. Many of the compositions discussed are proprietary alloys and they are protected by trademarks. A list of the trademarks and their owners is in­ cluded in the appendix.