As with so many British historians, the writer assumes intimate familiarity with individuals like the Earl of Shrewsbury (numerous of the Earls actually) and the Duke of Somerset, but in this case the individuals are less important than their group. This is a classic social history, albeit of a tiny group, the 382 English peers that existed from the beginning of Elizabeth the First's reign to the end of Charles I's (with 126 at the peak period in James's era). It can repeat itself, but it also helps the reader understand the shift from a medieval world to a modern one, and how the British aristocracy was part of that shift.
The most interesting parts of the book concern the shift from a violent, military aristocracy to one that attended to court balls and state sinecures. In the middle ages, the lords had hundreds of attendants, where even other gentlemen wore their livery and worked in their households, and they dominated local juries, courts, and assemblies, to the perversion of state justice. Henry VII however, passed acts demanding first loyalty to the king, enforced laws allowing livery only for household services, and fined Lord Bergavenny 70,000 pounds for retaining 471 men with him in Kent. Yet, as the author points, out within a few years that same lord contributed a 1,000 men to fight a battle. A third of all troops in the army still came indentured from lords. Elizabeth, however, demanded the peers work as county "Lord Lieutenant" to call up "Trained bands" directly for the Queen. While as late as the 1570s the Earl of Oxford traveled with up to a hundred bodyguards wearing his boar symbol, and lords would regularly kill each other and their aides in battles of dozens, within a few years Dukes ran around without any protection at all, and with total staffs of a few dozen. Broadswords and battles gave way to rapiers and the code duello. Peers gave up their castles for sprawling country houses, and their armories for London town houses.
For much of the book, in fact, it's hard to discern the "crisis," which the author implies led up to the aristocracy's fall in the Civil War. For instance, the aristocracy was increasingly impoverished during Elizabeth's penurious reign, but waxed fat under the spendthrift James. The total turnover of land doubled, and then halved after 1600. It's only in the conclusion that the author totals all the reasons the aristocracy lost in power and prestige. The peers' wealth declined relative to the gentry, their landholdings shrunk relative to their investments in paper and trading wealth, their military importance waned, the granting of titles for cash under the Stuart's sapped respect, the tenantry became only economically, not feudally, connected to their barons, they increasingly lived in London rather than in their country houses, and the Puritan undermining of respect for class all had their impact. Many of the aristocracy sided with the Roundheads during the war, but even those were stripped of their respect and their House of Lords. The aristocracy that emerged after 1660 and the death of feudalism, however, was also incipient in this time, in its focus on state service rather than war, its attention to bookish learning rather than physical pursuits, its increasingly involvement in trade, and so forth. The crisis of the aristocracy thus presaged its eventual rebirth, and its surprisingly leading part in the Industrial Revolution that brought England to the forefront of the globe.