Wavelets are a powerful class of bases that have varying frequency and duration. This is in contrast to the varying frequency but fixed duration of Fourier methods. In this lesson you will learn how the unique properties of wavelets can be used to localize signals in both time and frequency. You will learn that the wavelet bases are obtained by time shifting and scaling a mother wavelet and how the wavelet representation differs from the short-time Fourier transform. These introductory concepts will prepare you for the more in-depth understanding provided in subsequent lessons.