Albumen cabinet card photograph of Sir John F. W. Herschel (1792–1871), produced by the London studio of Maull & Polyblank. The portrait shows Herschel seated beside a writing table holding a quill pen, posed in later life with his characteristic white hair. The photograph likely dates to the 1860s. The mount is printed Maull & Polyblank, London, with studio addresses on the reverse. Sir John Herschel was one of the most important scientific figures connected with the early history of photography. A mathematician, astronomer, and chemist, he was the son of the astronomer William Herschel and nephew of Caroline Herschel. Beyond his astronomical work, Herschel played a central role in the development of photographic science during the 1830s and 1840s. He introduced the terms photography, negative, and positive into the language of the new medium and discovered that sodium thiosulfate (“hypo”) could be used as a photographic fixer, making permanent photographs possible. Herschel experimented extensively with early photographic processes including photogenic drawing and cyanotype, and maintained close correspondence with pioneers such as William Henry Fox Talbot and Anna Atkins. Although not primarily a daguerreotypist, Herschel conducted early experiments with light-sensitive silver compounds at the same time that daguerreotypes were being developed in France, placing him among the foundational scientific contributors to the invention of photography. The sitter is shown wearing decorations and honors awarded for his scientific achievements, including recognition by the Royal Society. Herschel served as President of the Royal Astronomical Society and made significant contributions to star cataloging and southern hemisphere astronomy during his work at the Cape of Good Hope. Printed photographer’s imprint and London studio addresses on the reverse, with later pencil identification reading “Sir William Herschel” and “Dr Hershel FRS,” referring to Sir John Herschel.