Modern air conditioning was invented by Willis Haviland Carrier on July 17, 1902. Carrier designed the first modern air conditioning system primarily to control humidity, which was a crucial factor for a printing plant in Brooklyn, New York, to prevent paper from wrinkling and ink from running. This invention combined temperature control and humidity control in a cooling system using cold water coils and a fan, laying the foundation for the air conditioning industry. Carrier later founded the Carrier Engineering Corporation, which played a key role in advancing air conditioning technology and making it more accessible. The concept and experimentation with cooling and humidity control had earlier roots, but Carrier's 1902 invention is considered the birth of modern air conditioning.