This chapter introduces channel and noise characterisation for Power Line Communications. Section 1.2 looks at PLC frequency bands and common topologies as these are possibly the most profound stage setters when characterising PLC channel and noise scenarios. Couplers may be of either inductive or capacitive nature with detailed coupling schemes introduced in Section 1.3. In the sequel, the aim of Section 1.4 is to provide information on measurement equipment and procedures that have been used to generate a plurality of results for various chapters throughout the book. Further, Sections 1.5 and 1.6 introduce the underlying concepts of PLC channel and noise modelling, respectively, and guide the reader to the more detailed chapters on each topic. This chapter is rounded off by an appendix that explains the basics of dual conductor transmission line theory, considered interesting background reading for those new to PLC signal propagation.