How the mind maps by topic came about

I created my first mind map about Wolfgang Amadeus Mozart. I put 15 intense book pages onto a DIN A3 sheet. Then I drew a few more things into it and had fun doing it. I exhibited it at an open day at my school, and the first boy who saw it learned the material, all the details I had listed, within a few minutes.
After his subsequent extemporaneous presentation on Mozart's life, I asked him if he had perhaps just given a presentation on the composer at school. But he denied it with a grin: "All I knew about Mozart was that he made music and was already dead."