I can think of no time of day more placid and still than four o'clock in the morning.

For better or worse, it was a time I inhabited all too often in my university days.

At the start of term, my supervisor cautioned us against striving for some misplaced idea of perfection. Think of each essay as a trial, an attempt, he said. No more, no less.

Being the incorrigible perfectionist that I was, I tried to get through as much secondary reading as possible before I started writing, half-hoping that inspiration would suddenly strike.

Of course, this hardly ever came my way. Most of my weekly essays were written in a mad rush at three or four o'clock in the morning, fuelled by equal parts caffeine and desperation.

Yet there was method in this madness. Unlike Gwen Stefani in her song of the same name, I did not stay up till "4 in the Morning", nor did any tears ever come "pouring" down. Knowing that I worked best in the early morning, I would make sure I went to bed by 10pm and woke up six hours later.

As a chronic procrastinator, I was all too familiar with the thrills and perils of living from deadline to deadline.

I spent a great deal of time wallowing in what Tim Urban, founder of the popular Wait But Why blog , calls the "Dark Playground" of guilt, anxiety, self-hatred and dread as I put off doing what I should have started long ago. "Playground", however, is a bit of a misnomer - when I procrastinated, I often did the dishes and vacuumed the floor.

But 4am. Four o'clock in the morning was that magical hour betwixt evening and early morning, when a hush would finally descend over my university hostel after the last of the party stragglers had retired for the night.

The hostel, built in the 1960s, had that hard-to-place synthetic smell that lingers in older developments like the Afro Asia Building - scheduled to be demolished this month - and The Projector.

The dormitory walls were notoriously thin, and adjacent rooms in my first-year corridor were linked by small fire doors you could sometimes climb through if the insulating material between them had worn out.

When my next-door neighbour had company, I could make out snatches of their conversation. Once, on what must have been a particularly still evening, I even heard the sound of her typing.

(Wednesday Morning, 3 A.M. is the name of Simon and Garfunkel's debut studio album. It has The Sound Of Silence, something most people would expect from 3am on a weekday.)

Perhaps unsurprisingly, I worked best when everyone was asleep and I had nothing but my thoughts for company. Four o'clock was often that time of morning when the noises within and without subsided to a hum low enough for me to marshal my thoughts into sentences without distraction.

Too tired to feel anxious about working at the last minute, or be distracted by social media (goodness knows what poet T. S. Eliot would have made of the Twitter-shortened attention spans of people today), my mind narrowed into a channel that had bandwidth for one thing and one thing alone: Getting the job done.

If I was lucky, I would sometimes come close to what I think Hungarian psychologist Mihaly Csikszentmihalyi would describe as flow - a highly focused state of mind also known as "the zone". Everything around me would fade into a blur so there was nothing left except me and row upon advancing row of Times New Roman on the computer screen.

But the demands of social life, and my unpredictable working hours, would make it nigh impossible for me to get up at this hour every morning even if I wanted to.

The last time I did so was half a year ago, during my stint as a digital sub-editor, when I had to be in the office by 5.30am.

Early risers who do so out of daily habit are in pretty good company.

Apple's chief executive Tim Cook starts his morning routine at 3.45am. Haruki Murakami, like Voltaire and John Milton before him, gets up at 4am to write. Former US first lady Michelle Obama begins her workout at 4.30am, and Benjamin Franklin, known for his meticulous schedule, used to rise at 5am every day.

Irish novelist and playwright Edna O'Brien felt herself "nearer to the unconscious, the source of inspiration" in the early morning.

For some reason, 4am is usually the time that springs to mind when someone talks about working in the wee hours of the morning.

An hour earlier, perhaps, would be too ungodly, an hour later too common. The supposed prevalence of 4am in popular culture - from American singer Faron Young's 1971 hit single, to an episode of The Simpsons - even led to American performance artist Rives giving a TED talk on his conspiracy theory of 4am.

The spell of 4am is broken when the rest of the city stirs to life.

First, there is the sound of the early bird, like the one in Pulitzer Prize winner Elizabeth Bishop's poem, Sunday, 4.A.M., which "arranges/two notes at right angles". Then the traffic rises a pitch higher, and a horn pierces the morning's lingering calm.

In the same way, the rest of the day takes on a different tone depending on the time you get up - think of 4am and 6am as melodies unspooling in different musical keys - so too there are different types of 4ams.

The "midnight oil" kind, that temporal room borne out of sheer necessity, must surely kindle much fellow-feeling among 4am-ers around the world.

Four o'clock is the new midnight. More than just a moment, it is a place of refuge, a ritual, a state of mind.