This book will be regarded as the standard biography of de Valera for many years to come. The authors were given access to "his huge library of private papers". They also had "the benefit of his personal recollections of the great events in which he has played so prominent a part". It would be difficult to exaggerate the value of these sources to a biographer. But a price is paid: in this case, a high price.
There is; a virtual identification of authors and subject. Despite de Valera's steadfast refusal to write an autobiography, he has achieved the same result in a book that is more a self image of the subject than a biography proper. This is, indeed, in large measure an apologia - a justification.
Inevitably one looks here for some clear characterisation of a complex man whose whole life has been spent in the public eye. After a half-century of political strife and achievement, de Valera still chooses to present himself as the intellectual mathematician, the schoolmaster reluctantly forced to shoulder the burden of office. The new glimpses of his family life support this view.
And what kind of public man? The emphasis here is on consistency, on simplicity, even on innocence. Writing of the Treaty debate, the authors say: "He had no desire to do anything which could be interpreted as underhand, despite his feeling that those in favour of the Treaty were not themselves acting fairly."
And they go on to quote a famous passage in which de Valera talks of being "sick and tired of politics." It is a view that political opponents will find hard to reconcile with their own entrenched image of de Valera. And little effort is made here to discuss the transition in de Valera himself from political innocence to experienced leadership.
No one would pretend that the tangled web of Irish politics between the Sinn Féin election of 1918 and the Pact election of 1922 is easily unravelled. It was a time of confusion. New men - and many of the political leaders were new - had to learn new roles: older men had to change established attitudes.
It was an easy time to make mistakes; if anything was to be done at all it was inevitable that mistakes would be made.
For all his dominance and charisma, de Valera, too, was limited in his choices by the views and attitudes of the men about him.
De Valera the politician was the product of his time. He came to prominence at a time when the status, political independence, and sovereignty of the new Irish state was the political issue. He remained, throughout his long public life, mainly concerned with these large issues of constitutional definition.
The tension in outlook and aim between de Valera and Seán Lemass is outlined; de Valera's mode of handling cabinet disagreement is mentioned. But we are given little new information. Only the brief chapters on family life offer new clues to the character of de Valera.
His reticence regarding the later years might indicate that a new leader (Lemass) had, in effect, taken over in the 1950s - that Lemass succeeded to the reality of power even before de Valera resigned as Taoiseach in 1959.
The concern of de Valera to justify and explain his role in the foundation years of the state helps to explain his continuing emphasis on constitutional issues and formulae, his pedantic precision, his dependence upon other men to carry on the day-to-day work of Party organisation and governmental administration.
Many of the political opponents of his own generation have remained obsessed with the man to the point that they have added to a political myth. The dominance of de Valera in Irish politics owes as much to his opponents as it does to his own personality and achievement.
They identified the man, rather than his party or its policies, as the most important factor in electoral contests and Dáil debates; they attributed many of their own failures to his political acumen.
In 1933, Seán Ó Faoláin wrote of de Valera: "He has turned, or is trying to turn, militarist Republicanism into constitutional Republicanism."
In the epilogue to the present book that same aim has become an achievement: "Gradually he established a Republican tradition which was genuinely democratic rather than military."
De Valera the elder statesman remains committed to the need to justify the de Valera of 1916-1922.