The Treachery Of Images (La trahison des images), a series of paintings, (1928–1929) are probably his most famous paintings. The picture at right is more commonly known as 'Ceci n'est pas une pipe' or 'This is not a pipe'. The viewer is encouraged to consider the distinction between reality and the representation of reality.
A common figure appearing in many of his paintings is a faceless, non-descript man in a suit wearing a black bowler hat. Frequently this figure would appear multiple times in the same painting--a metaphor for the normalizing power of modern existence and the doldrums of social constructs such as "the workday."
In Paris, Magritte's system of conceptual painting was formed, it remained almost unchanged until the end of his life. His painting manner, intentionally dry and academic, "polished in the technical sense" (p.18 Magritte. By Marcel Paquet. Taschen. 1992) with precise and clean draughtsmanship demonstrated a paradoxical ability to depict trustworthy an unreal, unthinkable reality. 
- René Magritte - Biography Olga's Gallery.