String field theory is a theoretical framework in physics that combines concepts from string theory and quantum field theory. In string theory, the fundamental building blocks of the universe are one-dimensional strings rather than point-like particles. String field theory extends this idea by treating these strings as fields, allowing for a more comprehensive description of their interactions and dynamics. This approach aims to unify the principles of quantum mechanics and general relativity, potentially providing insights into the nature of gravity and the fundamental forces of the universe. Researchers hope that string field theory can help resolve some of the challenges faced in understanding black holes, quantum gravity, and the early universe.