ABSTRACT
The invention of the accelerators in the 1930s and their rapid development after WWII opened up a new vista for fundamental physics research. The few particles that made themselves known in the early days of nuclear physics were only the tip of an iceberg. By the mid 1950s the accelerators produced so many new particles that physicists felt like eighteenth century zoologists facing a seemingly endless variety of “animals” to study. And just like the zoologists, they embarked on their classification.
