|  | ORIGINOFSPECIES | Influential work by 28-Across, familiarly | 
|  | PASSION | Further broadcast including one work by 28 (7) | 
|  | AFUNNY | Possibly night before attending discussion in work by 28 (1,5,5,8,2,3,3,2,3,5) | 
|  | ALMAGEST | Influential work written by the astronomer Ptolemy in the 2nd century AD; from Greek, 'greatest treatise' (8) | 
|  | ESSAY | John Locke's influential work, An ... Concerning Human Understanding | 
|  | SPOCK | Dr Benjamin _, US paediatrician noted for his influential work (5) | 
|  | OPERANT | Influential work performed at National Theatre (7) | 
|  | SEMIFINAL | Influential work covers function of leg getting to end of series (4-5) | 
|  | NEWTON | Scientist whose magnum opus Principia was published by the Royal Society with the help of Edmond Halley in 1687 and remains one of the world's most influential works | 
|  | EOLITH | Old stone implement, one carried by 28 when travelling | 
|  | EVE | First woman recruited by 28 (3) | 
|  | SEWN | Needled by 28 after swapping sides | 
|  | JUNIOR | One overwhelmed by 28 horror ultimately - one so young (6) | 
|  | JOAN | Old man's sweetheart portrayed as 20 by 28 (4) | 
|  | ELEPHANT | Size of writing paper; 23 by 28 inches (8) | 
|  | KOALA | Final blow by 28 with a marsupial (5) | 
|  | DIM | Sun set to the east by 28, getting dark | 
|  | BOATYMCBOATFACE | British research vessel that is essentially a 17 Across, was named by 28 Across, and is currently making climate-change discoveries in 45 Across | 
|  | THE | With 4-Across and 12-Across: song performed by 28-Across at the Summer Olympics in Atlanta in 1996 | 
|  | NEPTUNE | Main power for 9, visited by 28 2 on a 16 (7) |