Short Answer 
Modernism, a literary movement emerging in the early 20th century, is characterized by disillusionment and a rejection of traditional values, influenced by events like World War I and the Great Depression. Postmodernism, which arose after World War II, takes a satirical and fragmented approach to storytelling, questioning absolute truths, as seen in the works of authors like Kurt Vonnegut, and reflects the cultural shifts of its time.
Step 1: Understanding Modernism
Modernism is a literary movement that emerged mainly during the early twentieth century, influenced by significant events such as World War I and the Great Depression. This movement is often characterized by a strong sense of disillusionment and a conscious rejection of traditional values. Notable authors like Ernest Hemingway became prominent figures during this time, reflecting the complexities and uncertainties of modern life.
Step 2: Exploring Postmodernism
Postmodernism followed Modernism, gaining traction after World War II. This movement diverges significantly from its predecessor, emphasizing a satirical approach to storytelling and often featuring a fragmented narrative style. Authors such as Kurt Vonnegut exemplify this movement, questioning concepts like ‘absolute truth’ and encouraging readers to think critically about reality and narrative.
Step 3: Historical Context and Influence
The literary movements of Modernism and Postmodernism were fundamentally influenced by the historical contexts of their respective eras. Key events shaped their themes, including:
- The disillusionment of individuals after the devastation of World War I (Modernism)
- The cultural shifts following World War II, including milestones like the moon landings (Postmodernism)
- The socio-economic factors that led to the Great Depression (Modernism)
Understanding these movements provides insight into how literature reflects and reacts to the challenges of its time.