While there are many good books in particle physics, very seldom if ever a non-specialist comprehensive description of Quantum Field Theory has appeared. The intention of this short book is to offer a guided tour of that innermost topic of Theoretical Physics, in plain words and avoiding the mathematical apparatus, but still describing its various facets up to the research frontier, with the aim to give a glimpse of what the human mind has been capable of imagining for dealing with the behavior of Nature at the most fundamental level.