This Topic considers two time-domain Fourier transform properties, namely how the spectrum is effected is a signal is scaled-in-time or shifted-in-time. The scale-in-time theorem is important as it shows that a signal with broad temporal coverage has a narrow spectral coverage, and vice-versa (which itself leads to the uncertainty principle). This property is useful for finding transform of signals of variable length given an atomic signal as a building block. The Topic then discusses the shift-in-time theorem, which has application in estimation of time-delays, which in turn can lead to applications in (for example) direction-of-arrival estimation. The importance of linear-phase as a result of time-delay is introduced.