This book celebrates the life and work of twelve mathematicians who were either born in Wales or who worked in Wales. When the Welsh national anthem was composed in 1856, Wales was at the centre of the industrial revolution, the country was transformed by engineering and technology, and scientific societies flourished across the length and breadth of the land. By 1859, Charles Darwin had published his _On the_ _Origin of Species_, and one of its outcomes in Wales was a growing tension between religion and science, which influenced peoples’ perceptions of their Welshness. By the end of the nineteenth century, that perception had narrowed to include its poetry, music, religion and little else. Following the popularity of his book _Count Us In_, the author adopts a similar style inviting us to take pride in our mathematicians and demonstrating how the tide has turned.