Over the course of his decades-long career, Brooks's art transitioned from figurative and landscape paintings to abstract works and mixed media collages.
Brooks began to experiment with collage while visiting Paris in 1961. Years later, he wrote, "I have developed an acrylic collage medium that has become my favourite form of expression and is as natural to me as a painting device as oil or watercolour that I still love to do." By then he had developed a habit of collecting diverse materials for his collages, including old newspapers, posters, sheet music, letters, account ledgers, pieces of fabric and egg cartons, among other items. This process of collecting and collaging materials from his surrounding environments led critics to consider each collage a sort of abstract visual journal. Brooks's collages commanded years of his attention, and became, over time, some of the most widely celebrated works in his oeuvre.
Today Brooks's artworks are held in numerous public galleries, including the National Gallery of Canada and the Museum of Modern Art, Mexico City.