Giambattista della Porta (1535?[2] – 4 February 1615), also known as Giovanni Battista Della Porta, and John Baptist Porta [3] was an Italian scholar, polymath and playwright who lived in Naples at the time of the Scientific Revolution and Reformation.

Giambattista della Porta spent the majority of his life on scientific endeavors. He benefited from an informal education of tutors and visits from renowned scholars. His most famous work, first published in 1558, was entitled Magiae Naturalis (Natural Magic). In this book he covered a variety of the subjects he had investigated, including the study of: occult philosophy, astrology, alchemy, mathematics, meteorology, and natural philosophy.

His interest in a variety of disciplines resulted in the technological advances of the following: Agriculture, Hydraulics, Military Engineering, Instruments, Pharmacology. He published a book in 1606 on raising water by the force of the air. In 1608 he published a book on military engineering.

Additionally, della Porta perfected the camera obscura. In a later edition of his Natural Magic, della Porta described this device as having a convex lens. Though he was not the inventor, the popularity of this work helped spread knowledge of it. He compared the shape of the human eye to the lens in his camera obscura, and provided an easily understandable example of how light could bring images into the eye.

Della Porta also claimed to have invented the first telescope, but died while preparing the treatise (De telescopiis) in support of his claim. His efforts were also overshadowed by Galileo Galilei‘s improvement of the telescope in 1609, following its introduction in the Netherlands in 1608.