Ian Bradley's brilliant exploration of the spiritual and religious heart of monarchy, "God Save The Queen", has been updated and re-released for the Diamond Jubilee year by Continuum Books.
His particular focus is on the reign of Elizabeth II, but he also looks at the ideas of the Prince of Wales, to enlighten readers about the nature of one of the most important and least regarded institutions in modern Britain.
Bradley delves into centuries of British history to explain the thoroughly Christian evolution of the British monarchy. He also takes in the theological aspects - looking at the origins of sacred monarchy and kingship in the Old Testament, and exploring the character of a Christian king revealed through Christ in the New Testament – as well as taking time to unpack the coronation and the symbolism wrapped up in all the rituals and trappings.
There are moments of humour, as he tells of some of the coronations of monarchs past, including one who "left the happy banquet and the fitting company of his nobles for the caresses of loose women", and another who apparently laughed throughout the proceedings.
Importantly, he reflects on the last sixty years of the Queen's reign, the challenging scandal-ridden decade of the Nineties, the rise of celebrity and the tabloid press, and the transformation of Britain into a multi-faith and increasingly secular country.
As he notes, the changing beliefs and attitudes in Britain – not least to religion and to concepts of authority – have not been without their impact on the nature of monarchy.
While the monarchy's political power has all but vanished, the role as the nation's representative and a force for good have increased hugely. Philanthropy is, Bradley argues, now one of the four key roles of a British monarch, alongside spiritual leadership and exhortation, ceremonial splendour and personal example.
Hence the Queen's "tireless championship and patronage of voluntary public service", alongside her keen interest in Church matters, her publicly spoken respect for her own and other faiths, and regular appeals to her subjects to love and serve one another along Christian principles.
"Throughout the past 60 years, Queen Elizabeth II has exemplified that spiritual power and calling of monarchy," he writes.
"It would be hard to think of any Head of State in the world who has more consistently and faithfully embodied the principle of selfless, even sacrificial devotion to duty.
"Guided by a firm conviction in her calling and anointing by God, she has represented and articulated the spiritual feelings of her people in the most solemn and consecrated moments of the nation's life."
There are of course challenges, and these are duly considered. Should the monarch be the Defender of the Faith or Defender of Faith? Should the ceremony be Christian? Should the bar on Roman Catholics be lifted?
Despite changing ideas, Bradley concludes that there is still a lot to be positive about. Popular support for monarchy remains strong and in an age where fewer people are attending church but spirituality is thriving, he argues that this may in fact be the perfect moment for the monarchy to be "rediscovering and reasserting its spiritual heart".
In his Pause for Thought on BBC Radio 2 on Friday, the Archbishop of Canterbury spoke of the Queen being part of the "background" and suggested that we look more closely at the things that make up the background of our lives in order that we might be more thankful.
Fittingly in a year that is all about celebrating the Queen and her 60 years of public service, Bradley's thorough and engaging exploration of the British monarchy will leave you feeling how little you knew about one of the nation's most important institutions - and how much there is to appreciate.
As Bradley concludes: "Hereditary monarchy is a lonely, noble, sacrificial calling. It could do with being more loved and cherished by the churches."