This text is meant to cover all the field theory every high energy theorist should know, but not all that any particular theorist might need to know. It is not meant as an introduction to research, but as a preliminary to such courses: We try to fill in the cracks that often lie between standard field theory courses and advanced specialized courses. For example, we have some discussion of string theory, but it is more oriented toward the strong interactions, where it has some experimental justification, rather than quantum gravity and unification, where its usefulness is still under investigation. We do not mention statistical mechanics, although many of the field theory methods we discuss are useful there. Also, we do not discuss any experimental results in detail; phenomenology and analysis of experiments deserve their own text. We give and apply the methods of calculation and discuss the qualitative features of the results, but do not make a numerical comparison to nature: We concentrate more on the “forest” than the “trees”.