The Reactive and Refractory Metals Committee (RRMC) of WRC has seen the need for this interpretive report to highlight the increased usage of reactive and refractory metals and their alloys.These include beryllium, columbium, molybdenum, titanium, tantalum, tungsten and zirconium.Elements such as uranium, vanadium, and new materials in the family of composites will be briefly mentioned where joining information is available.The only restriction on the combination of metals joined is, that one of the metals will be of the aforementioned list above, e.g., beryllium to stainless steel, tungsten to molybdenum, titanium to Rene 41, etc.