In Chapter 8, the Mauna Loa CO2 data from 1958 to 2017 was decomposed to isolate the annual signal from the long-term trend. That exercise demonstrated that two non-interacting cycles, existing in the very same data set, can be considered separately. Once isolated, the amplitude of each cycle can be compared to identify the relative dominance of the different signals. Taking this to heart, a conceptual understanding of time series analysis can be developed.