AJS was the name used for cars and motorcycles made by the Wolverhampton, England company A. J. Stevens & Co. Ltd, from 1909 to 1931' The Stevens brothers began their career at the Stevens Screw Company, whose story began in 1800, due to their father Joseph Stevens. He built small 125cc 'Wearwell-Stevens' motorcycle engines in 1905. On that period, his sons decided to build their own motorcycles, wearing JAP engines. The year 1911 brought for AJS, the first production motorcycle, the 'Model A,' which had a single-cylinder 292cc side-valve motor with 2.75 hp. A year later, in 1912, the company put its first V-Twin 698cc three-speed 'Model D,' on the street. The model had 6 hp. Being successful and appreciated, the company received a lot of orders, so, it built a new factory in Wolverhampton. The 1920s were good for AJS, now being produced some models, from the 349cc single-cylinder 'Big Port' born in 1923, to the 349cc racing model 'K7'. On the same list there were the 498cc OHC model 'K10,' and 'M10.' In 1921, the engine grew up to 800cc. Till 1931, when the company began to experience financial troubles, AJS made a few cars with Meadows engines, manufactured car bodies for Clyno and made 200 buses and coaches.

　　In 1931, the company was bought by the Collier brothers London company Matchless and even if after a while, the Stevens brothers started a new company as Stevens Brothers (Wolverhampton) Ltd to make 3 wheel delivery vans, they could not use AJS brand because it belonged to the Colliers. The vans used a 588 cc single cylinder engine driving the rear wheels through a 3 speed gearbox and chain drive. The last ones were made in 1936.

　　The period 1935-1936 brought something new, Collier & Sons launching the 'Vee 4' touring bike and a racing version of this machine, with 55hp and a top speed of 135mph, a supercharger wearing the signature of Arnold Zoller.

　　The V4 was the followed by another model, 'Porcupine,' with a 500cc parallel-twin. In the 1940s and 1950s, the company was very proud of some models, the 7R, the 7R3, the 'Model 33,' the 250 and 410 'Stormer,' and 'MX' motocross bike.

　　Till 1969, when the AJS brand name disappeared for good, a few bikes built under Matchless signature were released, the AJS Model 33 being the last AJS four stroke produced. If we go back, we have to say that in 1938, Charlie and Harry Collier formed 'Associated Motor Cycles' (AMC) in 1938 and this is related to the fact that in 1966, AMC was sold to Norton-Villiers, which was buried in financial problems in 1974.