This book provides a state-of-the-art review of Pilot Wave Theory at the beginning of the XXI century. It contains the best contributions of the first International Conference on Advances in Pilot Wave Theory, held in Lisbon in 2021. The event brought together physicists from the new emerging field of Hydrodynamic Quantum Analogs (HQA) and philosophers of science. Three main themes were discussed: 1. Hydrodynamic quantum analogs, 2. Theoretical advances in pilot wave physics and, 3. Philosophical foundations of pilot wave theory. Recent experimental work in HQA has provided impetus to develop the pilot-wave approach into a realistic basis of quantum mechanics, specifically a dynamical completion of the existing theory of quantum statistics. To that end, the meeting featured theoretical work that advanced Louis de Broglie original pilot wave theory. This collection shows how several aspects of quantum systems have been reproduced in the hydrodynamic environment, and how the power of analogy suggests the possibility of a relatively intelligible quantum realm. Most notably, the notion of memory, as engendered in the pilot-wave-hydrodynamic system, suggests a profitable direction to explore in developing a more complete description of quantum phenomena. This book is expected to be of great interest to physicists, computer scientists and philosophers of science interested in the foundations of Quantum Mechanics. Chapter 1 and Chapter 12 are available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.