Adolph Gottlieb's work in the 1950s marked a significant evolution in his artistic journey, showcasing his deepening engagement with Abstract Expressionism and his exploration of new forms and ideas. The decade began with Gottlieb's experimentation in the "Imaginary Landscapes" series, initiated in 1951. In these works, he moved away from the grid structure of his earlier Pictographs to focus more on color and form. The "Imaginary Landscapes" feature compositions divided by an apparent horizon, where the lower portion contains elements reminiscent of his pictographs, and the upper portion hosts abstract shapes against a solid color block. This shift emphasized a stylistic move towards abstraction and a brighter color palette​ (The Art Story)​. By the mid-1950s, Gottlieb further distilled his exploration of form and abstraction in the "Unstill Life" series, showcasing a robust abstraction with a palette of blacks, grays, and reds. These works demonstrated a departure from the more defined grid structure to a focus on gestural line work and negative space, reflecting a modern slickness and movement within the composition​ (The Art Story)​. The late 1950s saw the development of Gottlieb's iconic "Burst" paintings, a series that represented a simplification of space and color. These paintings, characterized by a luminous disc floating above a tangled mass of brushstrokes, eliminated depth and horizon, making color and form the sole focus. The "Burst" series, starting in 1956, represented a significant contribution to the Abstract Expressionist movement, blending the emotional power of color with abstract form to evoke a range of responses from viewers​ (The Art Story)​. Gottlieb's work during this period was not only a visual exploration but also a philosophical inquiry into the relationship between the image and the spectator. His "Burst" paintings, with their vertical orientation and large scale, engaged directly with the viewer's physical presence, creating a visual-physical relationship central to the experience of Abstract Expressionism. These works were complete statements within themselves, where the two main forms and the canvas's physical dimensions all contributed to a delicate balance, echoing the transitory nature of emotional states​ (Frisson Art Gallery)​. An exhibition by Pace Gallery in 2019 titled "Adolph Gottlieb: Classic Paintings" drew together works from the mid-1950s until his death, highlighting the significant phase of his career during this decade. The exhibition underscored Gottlieb's role as a pivotal figure in abstraction and his continuous exploration of the possibilities within this territory​ (World Art Foundations)​. Gottlieb's artistic endeavors in the 1950s encapsulate his progression towards refining and defining his abstract expressionist approach, deeply influencing the trajectory of modern art. His exploration of form, color, and the experiential relationship between art and viewer reflects a profound engagement with the existential questions and aesthetic possibilities of his time.