This is the story of the greatest scientific discovery ever. The discovery that everything is made of atoms. The vast variety and richness of everything we see around us in the world and beyond, how it's built up, how it all fits together is all down to atoms and the mysterious laws they obey. As scientists delved deep into the atom, into the very heart of matter, they unravelled Nature's most shocking secrets. They had to abandon everything they believed in and create a whole new science. A science that today underpins the whole of physics, chemistry, biology, and maybe even life itself. But for me, the story of how humanity solved the mystery of the atom is both inspiring and remarkable. It's a story of great geniuses. Of men and women driven by their thirst for knowledge and glory. It's a story of false starts and conflicts, of ambition and revelation. A story that lead us through some of the most exciting and exhilarating ideas ever conceived of by the human race. And for a working physicist like me, it's the most important story there is. On 5th October, 1906, in a hotel room near Trieste, a German scientist called Ludwig Boltzmann hanged himself.