Using a method similar to that employed in his other books on psychoanalysis and Christianity, Michel Henry reads Kandinsky's philosophy of art through a phenomenology of Life. For Kandinsky, abstract, non-representational art allows the underlying and grounding affectivity and tonality of Life to become, in a certain sense, 'visible' (hence the title, Seeing the Invisible). That is, without the interference and mediation of represented objects, objects of the external and ek-static world, non-representational art displays the inner, clandestine Life of the pre-ekstatic horizon; it does so without directing the observer towards some phenomenal object (a house or a pair of shoes, for instance). So whereas a representational artist, like van Gogh, will paint a pair of shoes or a farm through a stylistic lens (impressionism in the case of van Gogh), Kandinsky will paint red circles, blue lines, and yellow triangles in order to (1) represent non-representable or ideal objects and (2) use these ideal objects to manifest the inner affectivity.
The world of Life, affectivity, and, to borrow from Kandinsky, tonality, are, according to Henry, what make the visible world possible. Only through these hidden dimensions are things such as farms and pairs of shoes possible.
I would only recommend this book to those interested in art and Michel Henry. If you're just interested in knowing about Henry's phenomenology of Life, you probably won't learn anything new about it from this book.