The Shannon-Hartley theorem is a fundamental principle in information theory that defines the maximum data transmission rate of a communication channel. It states that the channel capacity, measured in bits per second, depends on the bandwidth of the channel and the signal-to-noise ratio (SNR). This means that as the bandwidth increases or the SNR improves, the potential data rate can also increase. This theorem is crucial for designing efficient communication systems, such as telecommunications and data networks. By understanding the limits set by the Shannon-Hartley theorem, engineers can optimize the performance of these systems, ensuring reliable and fast data transmission even in the presence of noise.