What is the author's perspective in the nonfiction book, The Undoing Project?

Although the book is about the collaboration between Danny and Amos, the perspective of the book is not weighted equally between the two men, instead skewing heavily in favor of the perspective of Danny. This stems from a practical problem facing Lewis in conducting his research for the book: while Danny was still alive and happy to give extensive direct interviews with the author, Amos had been dead for several years. As a result of this, Amos’s perspective in the book is filtered through the perspectives and recollections of his friends, families, and colleagues.