This edition makes available for the first time the largest collection of unpublished material by the great eighteenth-century writer and lexicographer Samuel Johnson in existence. For the revised fourth edition (1773) of Johnson's Dictionary of the English Language, Johnson and his amanuensis annotated over one hundred and twenty interleaved folio pages of the first edition, but the printer for unknown reasons failed to include the corrections. These pages, including hundreds of authorial additions and changes to the text, are reproduced here in facsimile, along with a transcription, an extensive commentary and notes. This extraordinary archive offers a unique record of Johnson's methods of revision, his collaboration with his assistants, and the preparation of printer's copy in general. Johnson's deletion and editing of hundreds of new quotations, notes, and definitions contributed by others sheds much new light on his intentions for his work and his attitudes towards language and literature.