Leonardo da Vinci's drawings are among the most accomplished and technically varied ever made. Detailed study of those in the Royal Collection - the finest group in existence - reveals much about his materials and techniques and his innovative approach to drawing.

This ground-breaking book explores a substantial number of Leonardo's most celebrated drawings in unprecedented detail. Using specialist microscopic photography it will open up a new understanding and appreciation of Leonardo's techniques and present new information on his materials, uncovering features invisible to the naked eye. In addition, infrared images bring to light the artist's first touches (including Leonardo's own thumbprint, show in the detail below) and under-drawings, many of which have not been seen for 500 years.