Britain in the year 1936 had three kings upon its throne. George V died in January, he was succeeded upon his death by his son, Edward VIII, who then abdicated to his younger brother, George VI, in December. British author Adrian Phillips has written an excellent account of the year and how Edward made a right mess of things. Phillips' book is called "The King Who Had to Go: Edward VIII, Mrs Simpson, and the Hidden Politics of the Abdication Crisis".
Edward VIIl’s short, turbulent reign has been covered in a few books, mostly as part of larger biographies or in general histories of the year. (1936 was a very important year, even discounting the abdication.) Phillips' book is the first I've seen devoted directly to the abdication, and part of his title - "the Hidden Politics of the Abdication Crisis" - is what sets his book apart from the others. I think everyone knows about Edward's (known to his family as "David") love and devotion to Wallis Simpson, an American woman with "two husbands still living" and both a dubious past and present.
Prince Edward - the Prince of Wales - had long been worrisome to his family and the politicians who ran the government. He didn't marry and was attracted to married women who he kept as mistresses. He was a popular Prince of Wales, but his father George was dubious that he would be a good king. Unfortunately, as the oldest male child, Edward would succeed his father. In the early 1930's, Edward met Wallis Simpson in London and she soon took over from the previous mistress. By 1935, Edward was determined to both marry her and make her queen when he followed his father to the throne. And it is here where the politicians stepped in to manage - both sides - of the issue - should Edward marry Wallis and make her his queen or should he abdicate?
Winston Churchill, Stanley Baldwin, David Lloyd George, and Neville Chamberlain are only a few of the politicians and other important personages involved in the abdication. Churchill, by this time in his "wilderness years", supported Edward in his plans to keep both the throne and his lady, but failed badly with his support. The Conservative Party, led by Stanley Baldwin, worked with Edward but was in turmoil within the party. Would the government of Baldwin "hold"? The newspaper barons had their own intense interest in the case and published - when they were finally allowed to print details of the King and his romance - stories that affiliated their own political views. Adrian Phillips identifies everyone involved in the resolution of the King and Wallis messy problems and while the book is long, it's certainly never boring.
If you're looking for an excellent book on the Abdication and the people and the politics, this book's the one to pick.