What is it?
Perspective, in the context of vision and visual perception, is the way in which objects appear to the eye based on their spatial attributes; or their dimensions and the position of the eye relative to the objects. There are two main meanings of the term: linear perspective and aerial perspective.
The development of new forms of geometric projection in the construction of perspective corresponds with the invention of novel pictorial art forms of visual representation in the Italian Renaissance, since the fourteenth century and up till the end of the sixteenth century, and specifically within the circles of architectural and artistic experimentation and design. Treatises were composed on perspective by eminent theorists of art and architecture, including figures like Leon Battista Alberti, Lorenzo Ghiberti, and Piero della Francesca, also aided by experimental uses of optical devices through the installations of Filippo Brunelleschi. The investigations and writings of these Renaissance theorists of architecture and visual art were informed by the studies in classical optics of thirteenth-century Franciscan perspectivists like Roger Bacon, John Peckham, and Witelo, who were all directly inspired and influenced by the translation into Latin from Arabic of the Book of Optics (known in Latinate renditions as Perspectiva, and in Arabic as Kitab al-manazir) of the eleventh-century Arab polymath and optician, Alhazen (Ibn al-Haytham).
According to the book Practice of Looking: An Introduction to Visual Culture, Lisa Cartwright and Marita Sturken state, "Perspective refers to a set of systems or mechanisms used to produce representations of objects in space as if seen by an observer through a window or frame. In perspective, the size and detail of objects depicted corresponds to their relative distance from the imagined position of the observer" (page 151).