This is a summary presentation of TAU, a theory proposed to explain relativity and unify physics. It is a radical change, because it proposes six dimensions of space, instead of the usual three (normal physics) or nine (string theory). It starts with an alternative foundation for Special Relativity, and leads to a unified theory of physics. It is a realist theory because it is realist about space and time. The TAU concept is briefly introduced here, and its results explained in three main areas, particles, gravity and cosmology. In these areas it makes strong predictions and has several tests. This presentation is based around these applications and the key questions of completing a full particle model, and completing tests of gravity and tests of cosmology. These will decide its fate as an empirical theory. The aim here is to give an overview, in reasonable detail for generalists to see how the model works, but with a minimum of theoretical derivations, so we do not get too bogged down in equations. There are a lot of illustrations instead. Please note this is only a survey of the theory, and a more detailed introduction with proofs follows in Chapters 2-6, where it is developed in stages. In the first half here, we go quickly over the main concepts, in the second half, we give some equations for cosmology and gravity solutions in more detail, because they are more novel.