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 four parts: Part I: Quantum Computing: A Land Scape View, Part II: Quantum Algorithms, Part III: Error Correction Codes, and Part IV: Future Direction and Applications.