The direct method was a reaction to the grammar-translation method and focused on using only the target language in instruction. It emphasized spoken language and taught vocabulary through demonstration and pictures before introducing grammar inductively. Some key figures who adopted this approach were Gottlieb Heness, Lambert Sauveur, and Maximilian Berlitz, who founded language schools using these principles. The direct method's strengths included following a natural learning process and emphasizing communication skills, while weaknesses included a lack of structural practice and risk of incorrect rule induction.