David Harland describes the historical development of particle physics, and explains, in a non-mathematical way, how particle physics has influenced the structure of the Universe from the very beginning of time. He demonstrates the close links between discoveries in particle physics and in cosmology up to the present. He describes how our understanding of the Universe has developed from the discovery that the Universe is expanding, to the idea that all matter originated in a hot, Big Bang, then explains the many subtle improvements to the basic theory that have been necessary to understand how the very smallest particles and earliest structures (the ‘microscale’) in the Universe evolved to produce the Universe as it is now (the ‘macroscale’). The author also describes how scientists are attempting to develop a ‘Theory of Everything’ that would explain how an instant after the Big Bang a single primordial force was transformed into the four forces of nature that we observe today, which hitherto were believed to be ‘fundamental’.