Diffusion MRI was conceived in 1984 with an inspirational goal: To use a noninvasive technique to provide information on tissue at the microscopic level, while MR images remain at a macroscopic (millimetric) resolution, in other words, a kind of virtual, noninvasive biopsy. Denis Le Bihan, internationally recognized for his outstanding contributions to the development of new imaging methods, gives us a passionate insight in his work.