Editing List of inventors (section)

===H===
* [[Fritz Haber]] (1868–1934), Germany – [[Haber process]] (ammonia synthesis)
* [[John Hadley]] (1682–1744), UK – [[octant (instrument)|octant]]
* [[Waldemar Haffkine]] (1860–1930), Russia/Switzerland – first anti-[[cholera]] and anti-[[bubonic plague|plague]] vaccines
* [[Gunther von Hagens]] (born 1945), Germany – whole body [[Plastination]]
* [[Charles Martin Hall|Charles Hall]] (1863–1914), U.S. – [[aluminum]] production
* [[Robert N. Hall]] (1919–2016), U.S. – [[Laser diode|Semiconductor laser]]
* [[Samuel Hall (inventor)|Samuel Hall]] (1782–1863), UK – [[condenser (heat transfer)|condenser]] to enable recycling of water in a ship's steam engine
* [[Tracy Hall]] (1919–2008), U.S. – [[synthetic diamond]]
* [[Nicholas Halse]] (died 1636), England – malt kiln
* [[Richard Hamming]] (1915–1998), U.S. – [[Hamming code]]
* [[John Hays Hammond Jr.]] (1888–1965), U.S. – [[radio control]]
* [[Ruth Handler]] (1916–2002), U.S. – [[Barbie]] doll
* [[James Hargreaves]] (1720–1778), UK – [[spinning jenny]]
* [[John Harington (writer)|John Harington]] (1561–1612), UK – the [[flush toilet]]
* [[William Snow Harris]] (1791–1867), UK – much improved naval [[Lightning rod]]s
* [[John Harrison]] (1693–1776), UK – [[marine chronometer]]
* [[Ross Granville Harrison]] (1870–1959), U.S. – first successful animal [[Tissue culture]], [[Cell culture]]
* [[Kazuo Hashimoto]] (died 1995), Japan – [[Caller-ID]], [[answering machine]]
* [[Victor Hasselblad]] (1906–1978), Sweden – the 6 x 6&nbsp;cm [[single-lens reflex camera]]
* [[Ibn al-Haytham]] (Alhazen) (965–1039), [[Iraq]] – [[camera obscura]], [[pinhole camera]], [[magnifying glass]]
* [[George H. Heilmeier]] (1936–2014), U.S. – [[liquid crystal display]] (LCD)
* [[Henry Heimlich]] (1920–2016), U.S. – [[Heimlich maneuver#Abdominal thrusts|Heimlich maneuver]]
* [[Robert A. Heinlein]] (1907–1988), U.S. – [[waterbed]]
* [[Jozef Karol Hell]] (1713–1789), [[Slovakia]] – the water pillar
* [[Rudolf Hell]] (1901–2002), Germany – the [[Hellschreiber]]
* [[Hermann von Helmholtz]] (1821–1894), Germany – [[Helmholtz pitch notation]], [[Helmholtz resonator]], [[ophthalmoscope]]
* [[Zhang Heng]] (78–139), China – [[Seismometer]], first hydraulic-powered [[armillary sphere]]
* [[Beulah Louise Henry]] (1887–1973), U.S. – [[bobbin]]-free [[sewing machine]], vacuum [[ice cream freezer]]
* [[Charles H. Henry]] (1937–2016), U.S. – [[Quantum well laser]]
* [[Joseph Henry]] (1797–1878), Scotland/U.S. – electromagnetic [[relay]]
* [[Félix d'Herelle]] (1873–1949), together with [[Giorgi Eliava]] (1892–1937), France, Georgia – [[Phage therapy]]
* [[Hero of Alexandria|Heron]] (c. 10–70), [[Ægyptus|Roman Egypt]] – usually credited with invention of the [[aeolipile]], although it may have been described a century earlier
* [[John Herschel]] (1792–1871), UK – [[photographic fixer]] (hypo), [[actinometer]]
* [[Harry Houdini]] (1874–1926) U.S. – flight time illusion
* [[Heinrich Hertz]] (1857–1894), Germany – [[radio telegraphy]], [[electromagnetic radiation]]
* [[Ephraim Hertzano]] (1912–1987), Roumania / Israel – [[Rummikub]]
* [[Lasse Hessel]] (1940–2019), Denmark – [[female condom]]
* [[George de Hevesy]] (1885–1966), Hungary – [[radioactive tracer]]
* [[Ron Hickman|Ronald Price Hickman]] (1932–2011), U.S. – designed the original [[Lotus Elan#1960s Elan|Lotus Elan]], the [[Lotus Elan#1960s Elan|Lotus Elan +2]] and the [[Lotus Europa]], as well as the [[Black & Decker Workmate]]
* [[Rowland Hill (postal reformer)|Rowland Hill]] (1795–1879), UK – [[postage stamp]]
* [[Maurice Hilleman]] (1919–2005) – [[vaccines]] against childhood diseases
* [[Tanaka Hisashige]] (1799–1881), Japan – [[Myriad year clock]]
* [[Marcian Hoff|Ted Hoff]] (born 1937), U.S. – [[microprocessor]]
* [[Felix Hoffmann]] (Bayer) (1868–1949), Germany – [[aspirin]]
* [[Albert Hofmann]] (1906–2008), Switzerland – [[LSD]]
* [[Kotaro Honda]] (1870–1954), Japan – [[KS steel]]
* [[Huang Hongjia]] (1924–2021), China – [[single-mode optical fiber]]
* [[Herman Hollerith]] (1860–1929), U.S. – recording data on a machine-readable medium, [[tabulating machine|tabulator]], [[punched cards]]
* [[Nick Holonyak]] (1928–2022), U.S. – [[LED]] (Light Emitting Diode)
* [[Norman Holter]] (1914–1983), U.S. – [[Holter monitor]]
* [[Robert Hooke]] (1635–1703), UK – [[balance wheel]], [[iris diaphragm]], [[Tin can telephone|acoustic telephone]]
* [[Erna Schneider Hoover]] (born 1926), U.S. – computerized telephone switching system
* [[Harold Hopkins (physicist)|Harold Hopkins]] (1918–1994), UK – [[zoom lens]], rod lens [[endoscope]]
* [[Grace Hopper|Grace Murray Hopper]] (1906–1992), U.S. – [[compiler]]
* [[Frank Hornby]] (1863–1936), UK – invented [[Meccano]]
* [[Jimmy Hotz]] (1953–2023), U.S. – Hotz MIDI Translator, Atari Hotz Box
* [[Royal Earl House]] (1814–1895), U.S. – first [[Printing telegraph]]
* [[Coenraad Johannes van Houten]] (1801–1887), Netherlands – [[cocoa powder]], [[cacao butter]], [[chocolate milk]]
* [[Elias Howe]] (1819–1867), U.S. – [[sewing machine]]
* [[David Edward Hughes]] (1831–1900), UK – printing telegraph
* [[Kate Duval Hughes]] (born 1837) – window sash security devices
* [[Chuck Hull]] (born 1939), U.S. – [[3D printing|3D printer]]
* [[Troy Hurtubise]] (1963–2018), Canada – [[Trojan Ballistics Suit of Armor]], Ursus suit, Firepaste, Angel Light
* [[Miller Reese Hutchison]] (1876–1944), U.S. – [[Klaxon]], electric [[hearing aid]]
* [[Christiaan Huygens]] (1629–1695), Netherlands – [[pendulum clock]]
* [[John Wesley Hyatt]] (1837–1920), U.S. – [[celluloid]] manufacturing