Parseval's Theorem is a fundamental result in Fourier analysis that relates the total energy of a signal in the time domain to its representation in the frequency domain. Specifically, it states that the sum of the squares of a function's values over time is equal to the sum of the squares of its Fourier coefficients. This means that the energy of a signal is conserved when transforming between these two domains. In mathematical terms, if a function is represented by its Fourier series, Parseval's Theorem can be expressed as an equality involving integrals or sums. This theorem is crucial in various fields, including signal processing and communications, as it helps analyze and understand the behavior of signals.