Henry Stephens, MRCS (March 1796 – 15 September 1864) was a doctor, surgeon, chemist, writer, poet, inventor and entrepreneur. At medical school in London he was a friend of, and shared rooms with, poet John Keats, later wrote treatises on hernia and cholera, and conducted experiments to improve writing fluids and wood stains. In 1832 he invented an indelible blue-black writing fluid, patented it in 1837 and later formed the Stephens' Ink company which grew into a worldwide brand with a famous inkblot image.
Henry Stephens was born in Holborn, London, the second son of Joseph Stephens (1771–1820) and his wife Catherine (1763–1843), née Farey, but along with his elder brother John was soon moved to more rural Hertfordshire. The family lived briefly in Hatfield where sisters Frances (1798–1860) and Catherine (1800–1855) were born. Around 1801 they moved to Redbourn near St Albans where a fifth child, Josiah (1804–1865) was born. Joseph Stephens became the innkeeper at The Bull, the principal inn and busy staging-post in Redbourn High Street on a main stagecoach route between London and the north.
In 1811 Stephens was apprenticed to a local doctor in Markyate three miles north of Redbourn and in 1815 enrolled as a pupil in the united teaching school of Guy's and St Thomas' Hospital in London. He shared lodgings at 28 St Thomas Street, Southwark, with George Wilson Mackereth, whose daughter Stephens' son, Henry Charles, later married, and with John Keats, who was to become famous as a poet, and who died in Rome in 1821. It is on record that in 1816 Stephens helped Keats compose the line from Endymion book 1, "A thing of beauty is a joy forever ..."
On 14 March 2002, as part of the 'Re-weaving Rainbows' event of National Science Week 2002, Poet Laureate Sir Andrew Motion unveiled a blue plaque on the front wall of 28 St Thomas Street to commemorate the sharing of lodgings there by Keats and Stephens while they were medical students at Guy's and St Thomas' Hospital in 1815–16.