"Everything you ever wanted to know about conclaves (and papal transitions)" would not be a good description for this book. That, however, would not have been enough of a challenge for the author. What motivates him is arcana, demographics, obscurity, data analysis, history & trivia. Hence, a better description for this book would be "Everything you never realized you wished to know about conclaves (and papal transitions)". Hopefully, that gives you a flavor of what is in store.
It is detailed enough that all Catholic cardinals will find it of value – as was the case with the author's "The Next Pope 2011" book – which listed Jorge Mario Bergoglio (i.e., Pope Francis) on page 4 as a 'The Top Ten Papabili' two-years ahead of the 2013 conclave.This book builds upon, expands, embellishes, updates, refines & burnishes the wealth of sede vacante (i.e., papal vacancy) information & data that appeared in that book. In addition, this book includes all that happened during Pope Benedict XVI's reign and resignation, as well as Pope Francis' election and subsequent innovations, e.g., elevation of the 'irregular' cardinal bishops. The mode of presentation was also changed to deliver the information 'broadband' albeit in a structured, graduated and granular manner – i.e., lots of bullet points, summaries, tables, etc. The reader can easily pick and choose a path through the book. It does not have to be read sequentially.
The 'Table of Contents' and the liberal use of 'topic headings' will provide ample navigational clues. Exploit online browing features to peruse some of the pages and 'front matter'. You are unlikely to be disappointed. This book was not written for monetary gain, instead it was all about posterity. It is the author's 34th book and his 12th related to popes. It was a book he had not intended to write. He was toying with an autobiographical book, but felt the call of destiny. With his 'Papal Names' book he had compiled a body of unique research that would gainfully serve future generations. He felt that he had to do something similar re. conclaves. Hence, this book. A book that is intended to be a credible baseline reference on all aspects of conclaves up to and including the conclave to elect Pope Francis' successor. This is the 4th edition of this book -- published in November 2020. It very well might be the last edition since the author, yet again, is moving onto write about his other interests.