Gerardo Murillo, known as "Dr. Atl" (Guadalajara, Jalisco, 1875 – Ciudad de México, 1964), was a pioneering mexican artist and intellectual. He began his artistic studies in his hometown and continued at the Escuela Nacional de Bellas Artes (National School of Fine Arts) in Mexico City. After receiving a scholarship from the government, he studied Law and Philosophy in Europe, where he also worked as a journalist and painter. He earned a silver medal at the Salon of Paris in 1900 and became known as "the Agitator" for his critical stance against the academic methods of art instruction in Mexico.

Murillo's life was marked by his strong political and social activism, both in Mexico and during his time in exile. He founded the Liga Internacional de Pintores y Artistas (International League of Painters and Artists) and supported the constitutionalist movement during the Mexican Revolution. He was also incarcerated for his ideals. After living in the United States for a time, he was repatriated and became the director of the Escuela Nacional de Bellas Artes  (National School of Fine Arts) between 1914 and 1915 following Alfredo Ramos Martínez' resignation.

In the 1930s, Dr. Atl reached his artistic peak, focusing on landscapes and portraits, including notable works of the painter and poet Carmen Mondragón “Nahui Olin”, with whom he had a romantic relationship with since 1921. His volcanic landscapes, featuring the Popocatépetl, Iztaccíhuatl, and the Paricutín volcano, became emblematic of his work. He also invented the Atl-colors, a new type of pigment that revolutionized his painting technique. Dr. Atl donated much of his artwork to the Instituto Nacional de Bellas Artes (National Institute of Fine Arts).