I received this book free for an honest review.
Oil Painting Essentials covers the concepts and procedural essentials for several different genres of oil painting. It covers several genres: still life, interior, landscapes, portraits, figures, while also incorporating a section on plein air painting (painting 'on location', which is necessarily a different style).
In each section Keutz provides pictoral examples of his own work that exemplifies the conceptual and process essentials he is expounding. This is done to good effect, especially with regular use of in-progress examples showing the progression of a work from start to completion.
Of course, given that the discourse and examples come from one artist, these essentials are geared toward his style of painting, which may not necessarily bring fulfillment to all aspiring oil painters. That said, many of the general concepts carry through to any style, especially the light/dark near/far concepts that are presented throughout the various sections of the book. Discourse on perspective is also a universal concept, unless of course you aspire to be the next Picasso.
This is not a 'how-to-paint' book. There is no technical discourse on the use of oil paints, mixing, fattening of paint with oil for higher layers, etc. are not covered here. This book exemplifies artistic concepts that can help those who know the basics to better grasp the principles that will enable their painting to be more believable and catching to the eye.
While I do not have a lot of time to pursue oil painting, I will be hanging onto this book so that I can, hopefully, pursue the hobby and have a head start with the principles laid out in this work.