as old as cave paintings? Silhouettes seem to resonate with how we perceive figures - our brains are finely attuned to the figure in the distance, can read in the gestures much information, such as intention - - -
These are some recent (well, a century old) silhouette pieces. They show a clear lineage from the Art Nouveau era that immediately preceded and the concurrent Art Deco.
More recent, though overlapping with the above time period is Alex Katz (b 1927) - still with us age 92)