This chapter gives an overview of the basic layout, instrumentation and operation of the compressive split-HopkinsonHopkinson bar. It gives the background information required for a researcher understand the operation, analysis, and limitations of HopkinsonHopkinson bar experiments on materials with yield stressYield stress of ~50–500 MPa, such as metals and engineering polymersPolymer. The intention is to enable researchers to intelligently use a HopkinsonHopkinson Bar as a testing tool within a wider project, whilst at the same time providing a solid foundation for those who wish, in time, to work more deeply with the technique. Very few references are given in this chapter, further reading is given in the Introduction, and, of course, in subsequent chapters.