She-Wolves: The Women Who Ruled England Before Elizabeth by Helen Castor was exceptionally good, definitely a 5-star non-fiction.
Of course, it doesn't hurt that it is about one of my favorite time periods, medieval Europe. It chronicles the lives, ambitions, successes, and compromises of four women rulers who tried to be king and who paved the way for Mary and Elizabeth Tudor, the first queens of England to rule on their own and not as consorts.
Matilda - the only surviving legitimate child of Henry I. Her brother was drowned when the White Ship went down, and although Henry I did name her as his heir, she fought and lost the crown to her cousin, Stephen. In the end, she was able to secure the crown for her son, Henry II, whom Stephen named as his heir. She was formidable - courageous, politically savvy, passionate about her cause, but able to sacrifice short-term triumphs for the long game, ensuring that her son became king.
Eleanor of Aquitaine - Henry II's wife and duchess of Aquitaine in her own right. She shared many traits with her mother-in-law, Matilda, and fiercely protected the rights of her favorite son, Richard. She was an able ruler and more than anything else, a survivor. Imprisoned by HII, she was able to endure long years of isolation by keeping her eyes on the prize and finding the inner strength to endure.
Isabella of France- wife of the hapless Edward II, reputed to be the very worst of all English kings. After it was clear that he would never allow her to help him be a good, or even passable, king, she figured out how to escape to France, secure her teenaged son, find a lover capable of leading an insurrection, overthrow the king, and see her son crowned King Edward III. Her downfall was that she wanted to rule her son, who was having none of that! Not so incidentally, her bloodline is what provided the excuse for the 100 Years War between England and France.
Margaret of Anjou - another strong woman married to a weak king. Unlike EII, Margaret's husband, Henry VI, really had no interest in being king or in the trappings of pomp and majesty. Margaret had a long, arduous strong time of it, battling the Yorkist aspirants to the throne during the War of the Roses. I found myself less sympathetic and more critical of Margaret, probably due to Philippa Gregory's The White Queen and the TV series of the same name, as well as Sharon Kay Penman's The Sunne in Splendour, and other Yorkist-leaning novels and histories I have encountered over the years. That said, she was definitely a she-wolf, but unlike the other three female leaders she was not able to secure the throne for her son.
The final chapter provides a look at the reigns of Mary and Elizabeth, pointing out changes in society that made their reigns possible...the lack of legitimate male contenders to the throne didn't hurt them either.
All in all, an excellent, readable, captivating look at strong women leaders. Castor didn't try to do everything in this book. She didn't attempt to write a definitive book covering all aspects of the lives and times and reigns of the four women, but she painted their portraits within a specific premise, namely that their experiences made the reigns of the Tudor queens possible.
Apparently, there's a BBC documentary called She-Wolves: England's Early Queens. Must figure out how to watch this!