For everyone who loves a good story, that of Essilor is exceptional: from provincial company to world leader in just fifty years, without help and in an extremely technical sector, despite competition from top Japanese, German and American companies. This pioneer of employee share ownership entered the CAC 40 without having looked to it – proving that in a competitive economy, the field is considerably more open than it appears. Xavier Fontanet leads us through this unique adventure and recounts all the strategic and human stages of an outstanding conquest. Two ingenious inventions lay behind this success: the organic lens and the progressive lens, levers used to enter every market around the world. The resulting confrontation with the top players in the sector allowed the teams to grow through constant competition in fresh geographical territories: China, India, Korea, Japan, as well as the USA, Brazil, Australia and of course Europe. The company has demonstrated an uncommon ability to combine research, finance, commerce and industry. It was also set apart by its talent for forging successful alliances with local partners. Creating and maintaining a climate of trust in this way provided a pleasant working environment for everyone and proved to be a highly effective managerial approach. The keys to Essilor's success lie in these "in-house" skills. Knowing them is an invaluable entrepreneurial lesson for anyone interested in developing their business.