The Lotus 18 is one of the Lotus entries the open record knows by name, and by little else. That is not nothing: a name in the catalogue is where a car's story starts to be recoverable. Its designer of record is Colin Chapman.
The background
The Lotus 18 was a race car designed by Colin Chapman for use by Lotus in Formula One, Formula Two, and Formula Junior, which was used from 1960 until 1966 in F1.
Where it sits
Where it sits in Lotus's history is not in doubt: the 16 came before it; the 21 followed it. Its Lotus stablemates include the Lotus 100T and the Lotus 101.