Tamoxifen was first approved in 1977 and up to now remains a noteworthy therapeutic weapon to treat mainly breast cancer. However, further considerations exist regarding the tamoxifen profile. This book discusses recent research and future perspectives in the tamoxifen field. The topics discussed include tamoxifen pharmacokinetics, pharmacodynamics, adverse effects, clinical indications, therapeutic drug monitoring, autophagy mechanisms, tamoxifen topical formulation and breast cancer risk prevention, the use of tamoxifen in an oestrogen-independent manner for various neoplasms (Hepatocellular carcinoma, renal cell carcinoma, high grade glioma), mechanisms of resistance, potential role of CYP2D6, tamoxifen and antidepressants interaction in a psychiatric view, obesity influence in tamoxifen treatment, electrical pulse-mediated tamoxifen delivery, and tamoxifen in melanoma treatment.