The Type 25 was the first Grand Prix car to have a monocoque chassis.
The 25 made its debut at the 1962 Dutch Grand Prix, the first race of the season.
Jim Clark qualified 3rd on the grid and led the first 11 laps before the clutch failed.
Clark went on to win 3 races in the 1962 season and finished second in the World Championship behind Graham Hill. Lotus also finished second in the Constructors Championship.
1963 proved to be a great year for Lotus in Formula One.
Jim Clark became World Champion, dominating the season with 7 wins from 10 starts (That feat wasn�t beaten until 1988 when Ayrton Senna won 8 races out of 16).
Clark�s teammate during the season was Trevor Taylor, but he only had one top 6 finish during the season.
But Lotus still won the Constructors Championship, to take the first of many "Doubles".
Lotus continued with the 25 in 1964, though the Type 33 made its debut at the German Grand Prix.
Lotus also slipped to 3rd in the Constructors Championship, but they would be back.
Jim Clark used a 25 for the final time in the 1965 French Grand Prix, in a fitting farewell, the car won the race from Pole position and set the fastest lap along the way.
The chassis comprised two folded sheet box sections on either side of the driver.
Tubular extensions at either end of the chassis carried the engine and transmission at the rear, while the radiator, suspension and steering were placed at the front.
The lightweight steel monocoque chassis would set the trend in racing car design for at least 10 years.
Before that, Clark won 3 out of the first 5 races with the 25.
Peter Arundell drove the other Lotus for the first 4 races of the season.
Arundell was a good number 2 to Clark, scoring 11 points from his four starts.
Mike Spence replaced Arundell for the last 6 races of the season and finished well with a 4th place in the Mexican Grand Prix.
Clark finished 3rd in the Drivers Championship, though 33 development during the season would pay dividends the following year.
