For devotees of mid-century modern style, the mention of Charles and Ray Eames always elicits enthusiasm and zeal. How could it not? The husband and wife pair—known for such pieces as the Molded Plywood Lounge Chair (1946, Lounge Chair (1956), and Tandem Sling Seating (1962)—are two of the most important designers of the twentieth century. Their designs became iconic works being studied, lauded, and often outright copied. But what made the couple's work so prolific and significant? Here are four notable aspects of Charles and Ray’s work that helped them reach worldwide prominence.