Historian Samir Puri explains what inspired him to explore how imperial powers have shaped the world we live in today.
A decade ago, I witnessed a milestone in the Irish peace process, when an agreement was reached to devolve policing and justice powers from London to Belfast. Taoiseach Brian Cowen and Prime Minister Gordon Brown stood side by side as the joint guarantors of the Hillsborough Agreement. Heated negotiations came down to the wire before the deal was done with a politically weakened Peter Robinson of the DUP and Martin McGuinness of Sinn Féin in February 2010.
I was a junior civil servant in the British government working to support the process and, as an impartial generalist, had no axe to grind one way or another. In fact, back then, I didn't know much at all about the history of Anglo-Irish relations. And why should I have done?
There was just one moment in my youth when Northern Ireland's Troubles briefly touched my life. The Real IRA detonated a bomb in August 2001 in Ealing, west London: it exploded just after midnight, thankfully not killing anyone, but shattering the sheet glass of shopfronts along my bus route to school.
The stories I heard when growing up naturally related not to Irish history, but to my own background. My family had somehow managed to traverse three continents in three generations, from Asia to Africa to Europe - a migration that was undoubtedly an outcome of the British Empire's globe-straddling dominion.
My grandfather had sailed from India to Kenya in 1935, initially as an indentured labourer, toiling away on British railway construction. Later, as Commonwealth citizens living amid Africa's decolonisation in the 1960s and 1970s, my parents moved to the former imperial metropolis, London, where I grew up.
We are not habitually raised with the stories of other people's histories, which is why it takes real effort to see the world through someone else's eyes. For all the effects of globalisation and the information revolution, it is what we inherit from our immediate past that still carries the greatest emotional resonance. This is what makes us tick in terms of how we understand ourselves and, when we look across the world, how we understand each other.
Which is why, having long since left government service, I wrote The Great Imperial Hangover to capture how multiple histories unfold at the same time, each of great consequence to those close to it, but perhaps unseen by others.
And what a time to reconsider the themes of our different imperial legacies. Questions of identity and history are exploding into significance around the world.
The recent Hong Kong protests and the Black Lives Matter demonstrations offer two stark examples of how imperial legacies can haunt modern superpowers. For Hong Kong's Cantonese people, the unsteady balances that were established during the UK's handover of power to China in 1997 are tipping decisively against their sense of political identity. For many African-Americans, the bitter aftertaste of slavery, compounded by Donald Trump's divisive leadership, still has the power to set the US alight.
It is worth recalling that, for all the distaste that the word 'empire' leaves for many of us today, empires of some shape and size predominated since ancient times. They had existed for so long that we are still only getting used to their absence today.
Formal empires of some sort existed into the 20th century, ending only with the collapse of the European maritime colonial empires and, in 1991, with the Soviet Union's demise.
The way global power is exercised today reflects the fact that powerful countries seldom march off to formally take over new territories. So far, Russia's annexation of Ukraine's Crimea peninsula in 2014 remains the exception that proves this rule.
Now, instead of the formal empires of old, we have informal empires of economic and political dominance, such as those being forged by China, or by the US after World War II. For now, the age of formal empires is over.
These history lessons are crucial to putting into some context the state of our world. Every nation today, rich or powerful, large or small, exists in the long shadow of the end of the age of formal empires.
The world is addled with post-imperial legacies. As they heal in one nation, they reopen elsewhere. Our ability to progress to a more harmonious future depends in no small measure on the wisdom and empathy with which we grasp the world's varied imperial inheritances.
To deny how empires may have influenced our heritage would be to cut off our nose to spite our face. Positive things also flowed, for instance, the migratory patterns that have created thriving modern communities.
Take the Leo Varadkar family's roots. His father, Ashok, hails from Maharashtra, and how he came to practise medicine in Ireland not long after India's independence is itself a post-imperial story of sorts, and a wonderful one at that.
'The Great Imperial Hangover' by Samir Puri is published by Atlantic Books