Drawing is one of the oldest forms of human expression
The Viewing of the Aviators, By Eric Buechel, India Ink Wash and Airbrush, Sheet Size: 22" x 30", 2016
Drawing is a form of visual art in which a person uses various drawing instruments to mark paper or another two-dimensional medium. Instruments include graphite pencils, pen and ink, inked brushes, wax color pencils, crayons, charcoal, chalk, pastels, various kinds of erasers, markers, styluses, various metals (such as silverpoint), and electronic drawing.
An artist who practices or works in technical drawing may be called a drafter, draftsman, or draughtsman.
A drawing instrument releases small amount of material onto a surface, leaving a visible mark. The most common support for drawing is paper, although other materials, such as cardboard, plastic, leather, canvas, and board, may be used. Temporary drawings may be made on a blackboard or whiteboard or indeed almost anything. The medium has been a popular and fundamental means of public expression throughout human history. It is one of the simplest and most efficient means of communicating visual ideas. The wide availability of drawing instruments makes drawing one of the most common artistic activities. - Wiki
Master drawings - Khan Academy
Study Room for Drawings and Prints - The MET
Pen & Ink - Philadelphia Museum of Art
Paul Cézanne's approach to watercolor
The drawings of Leonardo da Vinci
Paleolithic art, an introduction
Silverpoint Drawing Technique
Picasso at Work - Video
Classical Drawing Atelier: A Contemporary Guide to Traditional Studio Practic - Amazon