The invention credited with revolutionizing printing in the 15th century is the printing press, invented by Johannes Gutenberg around 1440. This great innovation utilized movable type, allowing for the mass production of written materials, which significantly reduced the cost and time required for book production. As a result, literacy rates increased, and access to knowledge expanded widely among the public. The printing press played a crucial role in the spread of ideas during the Renaissance, particularly in religious reformation, as it enabled the rapid dissemination of texts like Martin Luther's 95 Theses. It is often regarded as a pivotal factor in shaping modern communication.