This contributed volume explores the revolutionary impact of nanotechnology on breast cancer therapy, namely through the pioneering domain of nano-theragnostic. It emphasises the transformation of personalised medicine through the integration of diagnostics and therapy with nanomaterials. It analyses the influence of the tumour microenvironment on cancer advancement, particularly on metastasis. It discusses innovative diagnostic instruments, including sophisticated biosensors and liquid biopsy, that facilitate early diagnosis and accurate monitoring. Innovative therapeutic techniques, such as nanoparticles, liposomes, carbon nanotubes, and quantum dots, are examined for their potential to enhance diagnostic and therapy efficacy. The book highlights the importance of surmounting obstacles such as drug resistance and examines methods like photothermal and photodynamic therapy. The exploration includes the role of AI in improving diagnosis and therapy, as well as the importance of lifestyle modifications and psychological factors in cancer care. This book presents unique insights into the transformative potential of nanotechnology in breast cancer therapy, offering renewed hope for both patients and healthcare professionals. It is an insightful read for researchers, scientists as well as practitioners.