This book is a review and high-yield reference on the clinical molecular diagnostics of malignant neoplasms. It aims to address the practical questions frequently encountered in the molecular oncology practice, as well as key points and pitfalls in the clinical interpretation of molecular tests in guiding precision cancer management. The text uses a Q&A format and case presentations, with emphasis on understanding the molecular test methods, diagnosis, classification, risk assessment and clinical correlation. Starting with an update on the molecular biology of cancer, the book focuses on the topics related to molecular diagnostics and genetics-based precision oncology.