Focal therapy, or the “Male Lumpectomy,” is now a viable strategy between watchful waiting and potentially morbid whole gland radiation or robotic radical prostatectomy for prostate cancer. When the concept of treating prostate cancer focally was introduced in 2002, it was very controversial since prostate cancer was considered to be multifocal, requiring a complete gland treatment. Now, 20 years of experience shows that it was a seminal concept that would eventually change the paradigm of prostate cancer treatment, improving cancer results and markedly decreasing patient morbidity. This chapter explores the relatively new nonthermal ablation modality of Irreversible Electroporation (IRE) and its potential advantages over thermal modalities. The first study of IRE for prostate cancer conducted in 2007 and carried out on 16 patients is presented here. Progress since then and follow-up on some of those patients where available is discussed.