It shows a giant king-like figure looming like some menacing Saturn over a landscape, sword in one hand, Episcopal crozier in the other.

To peer even closer is to be startled again when you see that the Leviathan himself is actually made up of thousands and thousands of people.

This giant, it seems, is a composite of millions.

This is the image that comes to mind on practically every page of Tom Garvin's landmark book on Sean Lemass, handsomely published and lavishly produced by the Royal Irish Academy.

His Lemass is a Leviathan alright, king of Kildare Street and sovereign of the national economy since 1932, and yet he seems to have also been a kind of composite figure himself, a political giant composed of millions of other giants.

As Garvin shows in his cool, pungent prose, Lemass was the subject of an extraordinary amount of comparisons over the course of his epic career.

To list them is to feel something of the force of his personality as a veteran minister and finally as Taoiseach after 1959.

Some saw the ghost of Parnell in his moody disposition and earliest memories.

Some unionists said he was an Irish version of hardened post-war French socialists such as Leon Blum, Paul Ramadier and Guy Mollet.

His earliest views on a 'United States of Europe' provoked murmurs about Jean Monet as well.

Others saw a specifically Germanic, rather than French Huguenot, tincture here since Lemass was fascinated by Konrad Adenauer, the post-war chancellor of West Germany, and his finance minister Ludwig Erhard

De Valera said Lemass was the Benjamin of the cabinet, son of Jacob who dreamed of angel-strewn ladders extending to Heaven. This was an especially acute aside from Dev, since Benjamin lost a brother to the Egyptian slave traders, as Lemass lost a brother to Collins's hardmen in the special branch at Oriel House in 1922. Garvin handles this private tragedy with moving sensitivity, reminding us that Lemass had to wipe away a tear from his eye when Michael Mills asked him about Noel after he resigned the premiership in 1966.

Lemass's insistence that the hatreds of the 1913-23 period must not be passed on to the next generation spoke volumes for his own inner turmoil as a young man, and should cut a chastening swathe through the pantomime version of the period that is still insisted on by certain 'local historians'. Lemass was also compared with Alexander Hamilton, the economic whizz-kid who dreamed of turning the sleepy American colonies into an industrial Leviathan without rival.

For some, Lemass was a natural Keynesian, for others he was a local version of the blowhards Smoot and Hawley who tried to cut America off from the world in the Twenties through high tariffs.

Garvin does not spare us from the darker side of the Lemass legend.

His fellow internees during the 1919-23 period referred to him as the 'Jewman', a vaguely disobliging nickname, although not quite on a par with the persistent rumours that de Valera was the bastard son of a Spanish Jew.

Countess Markiewicz saw the gruff Lemass as Faust's demon, Mephistopholes, while those who watched his torrential labours as Taoiseach 40 years later said he would have made a great Raj era civil servant in Bombay or Calcutta, matching the young George Orwell stride for stride through the monsoons of the subcontinent.

Ken Bloomfield of the Stormont cabinet office was marginally less insulting when he wrote about Lemass's pinstripe suits and the general Al Capone vibe that followed him around.

Perhaps the most insightful comment ever made about Lemass was by Maurice Moynihan, cabinet secretary between 1936 and 1961, and someone who became something of a connoisseur of Taoisigh. Lemass was somewhat baffled by Moynihan's casuistic mind and by his mysterious work in the boiler room of all of de Valera's premierships since 1936.

Having watched Lemass spar with Sean McEntee for 30 years in the small, airless cabinet room in Government Buildings, he said simply that "Lemass was very un-Irish".

While Garvin sees Lemass as a hinge figure in our history, this is no mere billet-doux like John Horgan's previous biography was in places.

Garvin suggests that Lemass never really changed his mind about Irish unionism, and never really understood the sincerity of their British and Protestant identity. The Stormont pirouette of 1965, Ostpolitik Irish style, looks simply tactical from that vantage point.

He also suggests that Lemass was privately unnerved by the cultural revolution wrought by his economic revolution, and that he lacked the wily arts of de Valera and Moynihan in squaring up to aggressive bishops after 1959. (John Bowman's classic essay on how Lemass's plans to extend the National Library onto TCD grounds were wrecked by J C McQuaid in the early Sixties suggests a similar uncomprehending attitude towards ecclesiastical bullying).

Garvin also leaves a tantalising question in the air at the end and has us asking how much of Lemass's fabled success at Industry & Commerce and at war-time supplies was down to the work of civil servant John Leydon, the priest-like orphan from Roscommon whom Lemass idolised?

There is a great book to be written on that issue itself.

Tom Garvin has written a moving and affecting account of a life lived twice, one that calls to mind Patrick Kavanagh's poem in the Forties where he railed against the collapsing society around him.

Culture is always something that was.

Something pedants can measure,

Skull of bard, thigh of chief,

Depth of dried-up river.

Shall we be thus forever?

Shall we be thus forever?

He could hardly have guessed when he wrote this that one man of consequence was thinking the same thoughts, and that he would live to give a resounding 'no' to the final poignant question.

John-Paul McCarthy teaches Irish history at Exeter College, Oxford