We look to history for inspiration. And there is nothing more inspiring than people born to immense wealth and privilege who, against all odds, wind up famous.

Which is to say, I just finished Thomas Maier's "When Lions Roar: The Churchills and the Kennedys." It's an engaging sprint through 50 years of history, painting side-by-side portraits of fathers and sons.

From the good side of the Atlantic, we have Joe Kennedy and his brood. Across the pond, it's Winston Churchill and his only son, Randolph. The two families crossed paths constantly from the 1930s through the 1960s, with a relationship that ran the gamut from friendly to hostile.

The quick version:

Joe Kennedy, shady Irish-American businessman worth millions, aspires to be president one day, despite the immense anti-Catholic bias he'd have to overcome. He also wants his kids to be important.

Winston Churchill, half-American British nobleman and Renaissance man, wants to be Prime Minister. He also envisions big things for his son.

And we're off! At first the families have somewhat friendly relations. In the '30s, mutual friends bring Joe and Winston together, and Joe uses his business ties to help Winston invest and rake in money. Things get sour when Joe becomes the ambassador to England in 1937. Joe thinks it would be stupid for America to fight Hitler, while Winston, the leader of the opposition party, is shouting every day about the threat posed by the Nazis. When war finally breaks out, Winston winds up as Prime Minister -- and Joe falls from grace as a defeatist jerk.

On the Kennedy side, this shifts the spotlight to Joe's kids, who figure out the very delicate task of taking advantage their father's money and connections while distancing themselves from his politics. JFK in particular had a deep admiration of Winston, modeling a lot of his rhetoric and thinking on the example of the British leader.

On the Churchill side, Winston never leaves the spotlight; even after losing the PM spot after the war, he regains it in the 50s. Randolph aspired to be everything his father was: a brilliant speaker, a member of parliament, an accomplished author. But he never really lived up to the expectations everyone had of Winston's son. He essentially drank himself to death in his 50s and had a very complex love-hate relationship with his dad.

Maier spins a LOT of plates in this book, as he lays out the motivations and missteps of all the players. The two families did mingle alot; not only because of Winston's prominence in global affairs, but because Randolph became a close friend of the Kennedy sons (despite hating their father). Also in the mix: Joe Kennedy's daughters, Winston Churchill's daughters, the close friends and associates of each clan, FDR and his oldest son (who was partner to shady business deals with Joe Kennedy), and Aristotle Onassis (who was friend to both families).

For all the complexity, it's highly readable, broken down into digestible themed segments. If there's a big question hanging over the narrative, it's why the father-son dynamics were so different in each family. Joe Kennedy is sort of the bad guy in this story, but he figured out how to elevate his sons when his political career crumbled. Winston Churchill was a world-beater who wanted the best for his kids, but somehow fell short as a father.

It's interesting stuff, no matter who you're rooting for. Other takeaways:

* In this book, marriages are a farce. Almost everyone is cheating on a spouse or having an affair with a married person. The only exceptions are Winston Churchill and RFK. There are several accounts of high-ranking U.S. officials cheating on their wives with the spouses of prominent Brits. Pamela Churchill, Randolph's wife, slept with FDR aide Averell Harriman; Randolph resented this even though he was cheating on Pamela mercilessly.

* For all the mess about anti-Catholic bias, Joe Kennedy and JFK were, ironically, not good Catholics.

* I don't understand how Winston Churchill had the time to run a government, paint, write very long books, and engage in social functions. People like Churchill and Theodore Roosevelt seemingly had 10 extra hours in each day.

* I'm not a huge fan of the Kennedys, but they had awful luck. This book features the JFK and RFK assassinations, Kathleen Kennedy dying in a plane crash (with her British lover), and Joe being reduced to vegetable status by a massive stroke. If he enjoyed his sons' triumphs he never got to express it.