The edited book is a consolidated handbook on quantum computing that covers quantum basic science and mathematics to advanced concepts and applications of quantum computing and quantum machine learning applied to diverse domains. The book includes dedicated chapters on introduction to quantum computing, its practical applications, the working behind quantum systems, quantum algorithms, quantum communications, and quantum cryptography. Each challenge that can be addressed with quantum technologies is further discussed from theoretical and practical perspectives. The book is divided into five parts: Part I: Scientific Theory for Quantum, Part II: Quantum Computing: Building Concepts, Part III: Quantum Algorithms- Theory & Applications, Part IV: Quantum Simulation Tools & Demonstrations, and Part V: Future Direction and Applications.