Mention the word bombing in relation to Dublin, and what comes to mind for most people is the murder and maiming by UVF car bombs in May 1974. But over a quarter of century earlier, a night of such death and destruction occurred that it remains as vivid as if it was yesterday for those who survived it. On 31 May 1941, the German Luftwaffe dropped four bombs across the unsuspecting capital, killing more than 40 people, seriously injuring over 100 more, and leaving over 2,000 homeless. It was to be one of the most sensational, terrifying events in the capital's history – and one of which many people have never heard.


Kevin C Kearns, an Irish-American historian and author, has now written a book to set the record straight. The Bombing of Dublin's North Strand gives a fascinating account of that night, drawing on declassified documents from the Irish military archive and the Dublin city archive, but equally potently, from the oral testimony of the many survivors still alive.


For most Dubliners, all signs on that night were that it was going to be a warm Whit holiday weekend ahead. The war was something that was really going on 'over there', even though bombs had been dropped on Dublin, and in five other counties earlier in the year. Belfast had suffered its own blitz the previous month and taoiseach Eamon de Valera had dispatched fire brigades from the capital and from Dundalk to help his Northern neighbours and give assistance to almost 3,000 refugees. Squadrons of Luftwaffe pilots took their flight path up the east coast of Ireland, and had been flying over the city for months on their bombing missions to London.


It all sounds too close for comfort, but the majority of citizens were seemingly unfazed by the potential for a catastrophe. As for the authorities, the newly fledgling republic was ill-equipped for a bomb attack. Air raid defence systems comprised ancient World War I gas masks, some trenches dug in the city's public parks, and above-ground concrete shelters ridiculed as 'hen houses'. But there were air-raid sirens. Anti-aircraft searchlights and flares were sent up to stress to the Luftwaffe that they were flying over neutral territory and to urge them on their way out of Irish air space. And the pilots complied. Except on the night of 31 May.


The sirens inexplicably never sounded prior to the first three bomb blasts around 1.30am or the final 500lbs landmine dropped just after 2.00am. There are many theories as to whether the city was targeted deliberately, or if it was British intelligence successfully 'bending the beam' to confuse German pilots. The beam was a sophisticated method to guide bombers to targets by transmitting radio navigation signals on specific intersecting lines. By 1941, scientists in Britain were believed to have discovered a method to disrupt these signals, causing confusion and disorientation among Luftwaffe pilots.


But the biggest mystery is why a book on the events of that night in May 1941 hasn't been written until now. Kearns' narrative history puts readers on the scene, aided by the oral testimonies of those who recall the night, minute by minute. And it's those survivors who have given him at least one answer as to why the bombings have been overlooked in the city's history.


"For many of the people who suffered, it's their belief that historians didn't regard it a significant loss. Even at the time, de Valera considered it a political and military disaster, rather than a human tragedy. This was a little urban village on the northside and no important buildings were ruined, no important people were killed – but you can bet if something similar had happened in the wealthier suburbs of the southside, much more would have been written."


Kearns also says that although in Ireland there is a degree of recording of first-hand social history accounts for rural communities, there is no tracking of urban oral histories in Dublin. Over the past 35 years, while researching his nine previous books, the historian, who is based in Maine, has amassed "thousands" of testimonies from Dublin's working-class areas, particularly the North Strand and the Liberties. It was while recording those individual stories for other books that people would refer now and then to the bombings of 1941.


"I was astonished that not a single book had been written on the subject. And the odd paragraph in newspapers recalling the events invariably got their facts wrong." Apart from the immediate death and destruction, survivors say the social history of the city altered dramatically afterwards, and an old community where residents traced roots back for generations was gone forever. Those made homeless by the bombing were given houses in the "barren wilds" of new corporation housing developments in Cabra and Crumlin. But what remains most remarkable for Kearns is the vivid recall of the people involved, now in their 70s and 80s.


"If you were to ask many of them what they were doing yesterday, or last week, they might find it difficult to remember. But if you bring up that night in 1941, it's as if a bright light switches on. The detail they remember is quite amazing. And not only factually – they can even describe their feelings and emotions just before, during and immediately after the bombs fell. They are right back again in their night of terror."


The Bombing of Dublin's North Strand: The Untold Story, by Kevin C Kearns is published by Gill & Macmillan, price €24.99