On the occasion of the birth centenary of the discovery of electron, I discuss its role in the area of Elementary Particle Physics. I emphasize that the discovery of electron marks the end of the speculation era lasting more than 2500 years. The key developments leading to the discovery of electron by J.J. Thomson are mentioned. The standard model is briefly described. It is emphasized that this model is unsatisfactory in several respects, however no further progress beyond standard model is possible unless there is a dramatic advance in instrumentation.

11 pages, To appear in Resonance--Journal of Science Education