This is one of Rembrandt's most puzzling prints, and has been the subject of debate for over 300 years. The subject is clearly a scholar, surrounded by the tools of his trade - books, papers and an astrolabe. What is less clear is the significance of the apparition by which he is transfixed. A ghostly figure, surrounded by clouds, holds a mirror in its left hand, pointing to it with its right hand. To the left is a floating disc bearing an indistinct inscription, with the letters INRI at the centre. Whilst the current title was only coined in the early 18th century, it seems fairly safe to assume that this print is based on the legendary magician and alchemist: it is known that Christopher Marlowe's Tragical History of Doctor Faustus was performed in Amsterdam about 1650. One possible explanation is that the print shows the moment when a good angel, in the shape of the shimmering apparition, warns Faust not to enter into a pact with the devil. Another interpretation is that the print is meant to demonstrate that scholars, and mankind in general, no matter how keenly they search after knowledge, can only perceive the truth as if in a glass darkly - in other words indirectly and distorted. Human knowledge is limited, and it is only through Christ that we can partake of perfect knowledge hereafter.