"What is this Thing Called a Quantum Computer?" is a comprehensive and accessible guide to the world of quantum computing. This book delves into the fundamental principles of quantum mechanics, the architecture and functionality of quantum computers, and the groundbreaking algorithms that set them apart from classical computers. It explores the current state of the field, highlighting key players and technologies, and addresses the technical and ethical challenges that lie ahead. With a forward-looking perspective, it envisions the future applications of quantum computing in various sectors, from healthcare and finance to secure communication and artificial intelligence, making it an essential read for anyone interested in the revolutionary potential of quantum technology.