This second edition has been fully revised and updated and some topics have undergone minor changes. The text has been revised as necessary throughout to ensure that known errors were corrected and I am grateful to various people for pointing these out. This book is a bridge between material covered by a Physics A level course in Particle and Quantum Physics and ideas, discoveries and theories on the big questions of today's Particle Physics and Cosmology. Starting with A level topics, it takes the reader a step further by discussing theories and scientific evidence in greater depth. It extends the topics with links, examples and diagrams whenever possible, touching on mathematical techniques used at university level. The book is an opportunity to learn about theories on elementary particles, the Standard Model and the Higgs Boson, and at the edge of scientific research, such as Dark Energy and the Early Universe. The ideas presented in the book have been around for some time. Authoritative scientists have exposed the same concepts clearly and inspired many. Through my long career in teaching I have met many inquisitive, curious minds, who have been enthused and have articulated many interesting questions as a result. They have researched these topics as true independent learners. Nevertheless, many found difficult to filter relevant information from the large pool of different resources. As I helped them finding their own way, I made a number of notes from which the idea of this book stems, bringing these notes together. I have enjoyed working on the subject and reading about the exciting experimental results of these last years, not least the detection of gravitational waves. I am happy to see renewed excitement about some of the most difficult topics in physics and I hope that others will enjoy reading the book as much as I have enjoyed writing it. Since publishing it, I have revised and made improvements to the first editions, adding accuracy, quality and value to its content. This book can be read by anyone with an interest in our ever-evolving understanding of the universe. In particular, it can be used as a resource for EPQ projects and IB extended essays, or as a summer reading for students. The book assumes the mathematical competence adequate for an A level Physics course or equivalent, introducing some mathematical ideas that stretch to Further Maths, but these can be omitted on a first reading. I hope that this book will help quench your thirst for knowledge and understanding, fulfilling your curiosity and extending your horizon.