This paper explores the evolution of oneiric art through the analysis of five iconic artists—Hieronymus Bosch, William Blake, Francisco de Goya, Odilon Redon, and Salvador Dalí—and their works. The theme of dreams is examined in both Eastern and Western contexts, focusing on Western art from the Renaissance to the 20th-century avant-gardes. The techniques, styles, artistic intentions, and lives of the artists are also discussed. Dreams have been a source of inspiration for artists throughout history, often reflecting personal experiences and societal influences. In Western art, dreams are associated with mythology, religion, and allegory, while in Chinese art, they were less common until the Ming Dynasty. The Romantic movement further developed oneiric art by emphasizing emotions and dreams as essential aspects of life, often depicted with melancholy and individual fantasies. Hieronymus Bosch's works, such as *The Garden of Earthly Delights*, are highly skilled and surreal, often based on biblical stories. William Blake's *Jacob's Ladder* and *Queen Katherine's Dream* showcase his unique interpretations and expressive techniques. Francisco de Goya's *The Sleep of Reason Produces Monsters* blends realism and symbolism, critiquing universal follies. Odilon Redon's *Vision* and Salvador Dalí's *Dream Caused by the Flight of a Bee around a Pomegranate a Second before Waking* exemplify the Surrealist approach, blending reality and dreams with detailed and realistic techniques. The conclusion emphasizes that oneiric art remains a vital part of Art History, offering insights into historical contexts, cultural influences, and the inner minds of great artists. These artworks reflect the states of mind of their creators, influenced by personal experiences and the political and historical context of their time, providing valuable aesthetic and interpretative value for contemporary artists and art historians.This paper explores the evolution of oneiric art through the analysis of five iconic artists—Hieronymus Bosch, William Blake, Francisco de Goya, Odilon Redon, and Salvador Dalí—and their works. The theme of dreams is examined in both Eastern and Western contexts, focusing on Western art from the Renaissance to the 20th-century avant-gardes. The techniques, styles, artistic intentions, and lives of the artists are also discussed. Dreams have been a source of inspiration for artists throughout history, often reflecting personal experiences and societal influences. In Western art, dreams are associated with mythology, religion, and allegory, while in Chinese art, they were less common until the Ming Dynasty. The Romantic movement further developed oneiric art by emphasizing emotions and dreams as essential aspects of life, often depicted with melancholy and individual fantasies. Hieronymus Bosch's works, such as *The Garden of Earthly Delights*, are highly skilled and surreal, often based on biblical stories. William Blake's *Jacob's Ladder* and *Queen Katherine's Dream* showcase his unique interpretations and expressive techniques. Francisco de Goya's *The Sleep of Reason Produces Monsters* blends realism and symbolism, critiquing universal follies. Odilon Redon's *Vision* and Salvador Dalí's *Dream Caused by the Flight of a Bee around a Pomegranate a Second before Waking* exemplify the Surrealist approach, blending reality and dreams with detailed and realistic techniques. The conclusion emphasizes that oneiric art remains a vital part of Art History, offering insights into historical contexts, cultural influences, and the inner minds of great artists. These artworks reflect the states of mind of their creators, influenced by personal experiences and the political and historical context of their time, providing valuable aesthetic and interpretative value for contemporary artists and art historians.