One of the most complex – and rather confusing (yet impressive) – regulation classes to emerge in modern times has been the Le Mans Prototype (LMP) category as run at Le Mans, and in the American Le Mans Series (ALMS). As its title suggests, this class was conceived largely by the French Automobile Club de l'Ouest (ACO), the jealously-protective and over many decades famously autocratic organisers of the Le Mans 24-Hour race. Their LMP cars have reigned for years now as the fastest closed-wheel competition cars in worldwide road racing.

The Le Mans Prototype class emerged initially at Le Mans in 1992. In that time of austere recession the ACO could see the entry for its 24-Hour race falling under extreme threat. The old and quite successful Group C endurance category had lost support and was in its death throes, partly due to background politicking which concentrated attention – and hard-to-find sponsor support – upon Formula 1. So the ACO opened its legendary 24-Hour race entry to older-style Porsche 962 sports-prototypes, while a new class was also created for small-engined sports-prototypes using production-based power units.