| BLAZEDTHETRAIL | Did pioneering work |
| HERSCHEL | English astronomer (son of William Herschel) who extended the catalogue of stars to the southern hemisphere and did pioneering work in photography (17921871). |
| OMARKHAYYAM | Persian polymath who did pioneering work on cubic equations |
| BLAZEATRAIL | Do pioneering work (5,1,5) |
| BREAKNEW | (& 24-across) Do pioneering work, harrowing? (5,3,6) |
| ASHENDEN | WWI spy in W Somerset Maugham's pioneering work of the espionage novel genre |
| GEORGEBOOLE | Largely self-taught English mathematician whose "Laws of Thought" was a pioneering work in modern symbolic logic |
| OSTWALD | Wilhelm ___, German chemist noted for his pioneering work on catalysis; Nobel Prize in Chemistry (1909) |
| BLAZINGATRAIL | Doing pioneering work on fire at train track (7,1,5) |
| GREAT | The ___, Robert Conquest's pioneering work on the Gulag system in the 9 (5,6) |
| TERROR | Robert Conquest's pioneering work on the Gulag system in the 9 (5,6) |
| ANNA | Forename of Sigmund Freud's daughter whose pioneering work in child psychoanalysis is remembered with a blue plaque (4) |
| FRESNEL | Augustin-Jean, French civil engineer and physicist noted for his pioneering work in optics (7) |
| PAULZOLL | US cardiologist born in 1911 noted for his pioneering work on the cardiac defibrillator (4,4) |
| ANNING | Mary ___, whose pioneering work in fossil collecting was slow to be recognised by the scientific community (6) |
| AMPS | Units of electric current honouring the pioneering work of the "Newton of electricity" (4) |
| GREGORMENDEL | Pioneering biologist known for his work in genetics: 2 wds. |
| NEMO | "Little ___ in Slumberland" (pioneering comic strip) |
| BEATIT | 1983 hit with a pioneering video |
| TAKEONME | 1985 #1 hit with a pioneering video |
