It appears that the earliest public domain reference regarding automotive catalysis was from January 1959 and written by GM and presented at the annual SAE meeting in Detroit. The publication related hydrocarbon control of a gasoline vehicle using an oxidation catalyst. The results showed 85 – 100% hydrocarbon reduction over the temperature range 600 – 750oC, under different vehicle operating conditions from idle to accelerations. The catalyst contained no precious metals but the full chemical composition was not disclosed. However, interestingly air was required to be pumped into the exhaust as the application didn’t always operate under stoichiometric conditions, but operated periodically under rich conditions. Hence oxygen was required to oxidise the gasoline derived hydrocarbons. This current publication will review the first public domain paper referencing different aftertreatment technologies (such as TWC, LNT, DPF and SCR but not limited to these technologies) and compare the technologies to the current state of the art in aftertreatment technology. This historical review using Ricardo’s Powerlink database, which contains over 280 000 automotive publications, will show how far exhaust aftertreatment technologies have significantly enhanced emissions control over the last half a century for both gasoline and Diesel applications. A timeline will be given showing when various technologies were first presented into the public domain. This will indicate how long it has taken certain emissions control technologies to enter the market.