The Porsche world is divided into multiple factions: old cars versus new cars; air-cooled or water-cooled; and rear engine, mid-engine, or front engine. Amongst those cliques, the majority of Porsche purists vote air- cooled, and that subset is further divided between the 356 cars and the 911s. The air-cooled 911 group--1965 through 1998--is historically the biggest and most vocal. Within the air-cooled 911 world, there are further sub-genres: short wheelbase and long wheelbase; long hood and short hood; turbos; torsion bar cars; and later 964 or 993 cars.

Even with all of those vertically-aligned factions, one car stands as the totem of all good things Porsche; the one car that melts the warring factions; the car that defines the Porsche 911 as the sports car of the ages. That car is the 1973 Carrera RS.

And if the 1973 RS is truly the king of all things air-cooled, then the one book that is the titular head of all things written about that fabled car is this book: the Porsche Carrera RS, Written and published by Thomas Gruber and Dr. Georg Konradsheim, the original version was released in 1992.

It was to Porsche literature what the '73 RS was to the regular 911s. The content of that first edition so eclipsed all other RS books being published that it was similar to the performance gap between a RS and a 911S. They were not playing the same game. That first edition was published in a limited run of 3000. The book quickly sold out, and to this day they continue to demand extreme valuations to get an owner to let one go.

But the air-cooled cavalry has arrived. Now that fabled tome from 1992 has been republished and greatly enhanced. There are new details, facts, developmental back stories, and unpublished pictures. At 434 total pages, this new 2015 book adds 178 more pages to the previous edition. The research for the new edition required three years of investigation and collaboration with many of the factory insiders who were there. The 2015 edition is not a reprint but a thoroughly reworked and expanded version. Porsche gave the authors full access to the factory photo archives. The new version has multiple unreleased photographs. The first version of the RS book set the bar for a book covering a single model, and the newly released version evaporates that bar.

The book traces the history from the earliest Porsche racing forays to the development of the 911 to the need to build enough street versions of the RS to justify--in other words to homologate--the RS for racing, and the early attempts at understanding and utilizing aerodynamics to make the car safer and faster.

The steps that the factory had to utilize to weigh each car built and then rebuild the car to the customers' specs was incredible. The intense engineering focus that only Porsche could bring to the development of turning a production street car into the single most winning type of car in history: the 911.

All of that remarkable history is here. The book will once again be published in two versions, English and German, with 3000 copies in each language. The quality of this book, both in its content as well as its construction, fully justifies the not inconsiderable cost. For anyone who acknowledges the importance and impact of Porsche on the automotive landscape, this book is a must-have. Put it on your birthday, Christmas, anniversary, and Fathers and Mothers Day wish lists. No Porsche home library is complete without this book on the shelf.