Does a final theory really exist? And what does it feel like to spend your life searching for it? These are some of the questions the theoretical physicist Jesper Møller Grimstrup writes about in Shell Beach. It is a book about quantum gravity, about white-water kayaking, and about a life in science. It is about conferences and smoky offices, about the quest for a final theory, and about hitchhiking illegally through Tibet. Jesper Møller Grimstrup has been an active researcher in theoretical physics for the past 20 years and in Shell Beach, he combines his research in high energy physics with his personal adventures. It is a story that involves not only the science but also Kafka's novels, sci-fi movies, and surfing giant waves off the southern shores of Iceland. Shell Beach consists of several intertwined tracks, where hardcore meets soft-core. First, there is the science, which starts with quantum mechanics and relativity and then passes through the standard model of particle physics to end up with modern topics such as noncommutative geometry and loop quantum gravity. Second, there the philosophy, the idea of a final theory, and what we might expect to find, should our search one day come to an end. And finally, there is the personal journey, that begins with a young scientist with independent ideas, who is eventually pushed into an orbit without a job and funded by crowdsourcing. In fact, Shell Beach is the outcome of a crowdfunding campaign that Jesper Møller Grimstrup ran in 2016 - it is one of the perks to his supporters. A key theme in Shell Beach is the idea, that the theory of everything could turn out to be conceptually empty and tell us little of significance. That it will not provide us with answers to our most urgent questions such as "why are we here?" This idea, which Grimstrup's own candidate for a final theory exemplifies, is illustrated through literature and film, and is followed by the question: "what will it do to us if we find that theory?" What will happen to us, seekers of truth, if we actually find what we have been searching for and it turns out to be different than what we had hoped for? Where will we go when there is nowhere else to look for answers? Shell Beach is a rare peek behind the scenes of contemporary high-energy physics and mathematics, where Jesper Møller Grimstrup has been an insider in several of the key research communities such as loop quantum gravity and noncommutative geometry. In his book, Grimstrup invites the reader into the engine room of modern theoretical physics to see how this world works, who is in power, and what the struggle among researchers for ideas and academic position feels like. Shell Beach ends with the author taking the highly unusual step of creating a crowdfunding campaign for then as the first in the world to conduct his research outside of academia financed by private sponsors. Above all Shell Beach is a book about waterfalls. According to Grimstrup, doing research in theoretical physics is like kayaking huge waterfalls in slow-motion: "Our waterfalls are the ideas we pursue and like all big waterfalls you cannot scout them thoroughly from the riverbank - the only way to find out is to enter the main current and go over the edge". THE PRESS WROTE ABOUT THE DANISH EDITION: "Jesper Møller Grimstrup has written a formidable book. I have read many books about physics and science but none that compares to his book" - Jens Ramskov, Science Editor, Ing.dk" It hits the bullseye ... I followed all the trails, fascinated and nicely included. This is not an easy book to reference ... but if you seek the big question you'll end up with even more" - Maria Helleberg, POV-international