A hundred pages into William Manchester‘s, A World Lit Only by Fire: The Medieval Mind and the Renaissance Portrait of an Age, I peeked two hundred pages further at his “acknowledgements and sources.” There to my delight (and surprise) I read:
Let me set down those works which have been the underpinning of this volume. First—for their scope and rich detail—three volumes from Will Durant’s eleven-volume Story of Civilization: volume 4, The Age of Faith; volume 5, The Renaissance; and volume 6, The Reformation. The events of those twelve centuries, from the sack of Rome in A.D. 410 to the beheading of Anne Boleyn in 1536, emerge from Durant’s pages in splendid array.
Here was a popular professor of history and author (The Last Lion: Winston Spencer Churchill; The Death of a President: November 20–November 25, 1963; American Caesar: Douglas MacArthur 1880–1964) honoring the work of a popular amateur. Manchester also acknowledged his use of “[a]nother towering monument of historicism,” namely The New Cambridge Medieval History and its Modern sequel, and several other series, but he regarded Durant’s epic narrative as on par with them, even giving it pride of place. I wasn’t expecting such confirmation of my taste, but welcomed it.
One serendipity led to another. Browsing my copies of the three volumes Manchester cited, I found myself enjoying the diverse ways Will Durant (1885-1981) expressed not only awareness of the things upon which the successful completion of his project depended, but also what psychologists call “mortality salience.”
I then took down from the shelf Our Oriental Heritage, the series’Durant’s inaugural tome. 
As its preface drew to a close, I noticed that the author’s eloquent affirmation of purpose, excitement and hope betrayed hardly any awareness of limitations. Here are the words of a man undertaking a massive project in his fiftieth year, in the aftermath of Wall Street’s collapse, the memories of the Great War still fresh in his readers’ minds as the winds of its successor begin to blow in Europe. Where the latter will soon take Western Civilization, of course, he does not predict:
Since these ear-minded times are not propitious for the popularity of expensive books on remote subjects of interest only to citizens of the world, it may be that the continuation of this series will be delayed by the prosaic necessities of economic life. But if the reception of this adventure in synthesis makes possible an uninterrupted devotion to the undertaking, Part Two should be ready by the fall of 1940, and its successors should appear, by the grace of health, at five-year intervals thereafter. Nothing would make me happier than to be freed, for this work, from ever other literary enterprise. I shall proceed as rapidly as time and circumstance will permit, hoping that a few of my contemporaries will care to grow old with me while learning, and that these volumes may help some of our children to understand and enjoy the infinite riches of their inheritance. (March 1935)
Volume II, The Life of Greece, appeared in 1939, a year ahead of schedule; Caesar and Christ, five years later, as anticipated; 
The Age of Faith, the series’ fourth (and stoutest) tome, was brought out in 1950. (The War may have had something to do with the “delay.”) The specter of interruption haunts none of their prefaces. That changes in 1953 with the Volume V, The Renaissance:
If circumstances permit, a sixth volume, probably under the title of The Age of the Reformation, will appear three or four years hence, cover the history of Christian, Islamic, and Judaic civilization outside of Italy from 1300, and in Italy from 1576 to 1648. The enlarged scale of treatment, and the imminence of senility, make it advisable to plan an end of the series with a seventh volume, The Age of Reason, which may carry the tale to the beginning of the nineteenth century (December 1, 1952)
At age 67 Durant acknowledged that the onset of senility might bring the series to a premature end. But in fact more than two volumes lay ahead of him than behind. His awareness of mortality sharpens in the preface to Volume VI, entitled simply, The Reformation:
If the Reaper will stay his hand, there will be a concluding Volume VII, The Age of Reason, which should appear some five years hence, and should carry the story of civilization to Napoleon. There we shall make our bow and retire, deeply grateful to all who have borne the weight of these tomes of their hands, and have forgiven numberless errors in our attempt to unravel the present into its constituent past. For the present is the past rolled up for action, and the past is the present unrolled for our understanding. (May 12, 1957)
Durant, then 72, was convinced that the seventh volume would be his last. He did not then know that he would lengthen its title by one word: The Age of Reason Begins; or that he would explore its subject in three more books. Four years later, however, in that book’s preface, the imperative to share the fruit of his learning was again competing with the Reaper’s demands. He negotiated that balance with grace and humor:
I had hoped to conclude my sketch of the history of civilization with a seventh volume to be called The Age of Reason, which was to cover the cultural development of Europe from the accession of Elizabeth I to the outbreak of the French Revolution. But as the story came closer to our own times and interests it presented an ever greater number of personalities and events still vitally influential today; and these demanded no mere lifeless chronicle, but a humanizing visualization which in turn demanded spaced. Hence these reams. What had begun as a final volume has swollen into three, and one of the present authors, at an unseemly age, becomes a prima donna making a succession of farewell tours. (May 1961)
And so
Barring some lethal surprise to the authors or to civilization, Volume VIII, The Age of Louis XIV, should be ready in 1963; and if decay permits, a final volume, The Age of Voltaire, will appear in 1965.
During the Cold War, the thought of a “lethal surprise to civilization” was in the background, when it did not elbow its way into the foreground, of civilization’s heirs. Durant clarified his reference to “authors” in this preface’s final sentence: “Mrs. [Ariel] Durant’s part in these concluding volumes has been so substantial that our names must be united on the title page.”
As it happened, providence barred both surprises and decay did permit Volumes VIII and IX to be born on schedule. Their prefaces reflect the authors’ awareness of political as well as biological contingency:
We hope to present Part IX, The Age of Voltaire, in 1965, and Part X, Rousseau and Revolution, in 1968. Some difficulties have arisen, partly from the wealth of material offered by the eighteenth century, all demanding study and space. Meanwhile we shall rely on the Great Powers not to destroy our subject before it destroys us. (May, 1963)
Will Durant was in his 82nd year when Volume X was ready in May 1967, well ahead of schedule. The preface to IX shared no intimations of mortality, but the one for X announced:
This is the concluding volume of that Story of Civilization to which we devoted ourselves in 1929, and which has been the daily chore and solace of our lives every since. . . . We shall not sin at such length again; but if we manage to elude the Reaper for another year or two we hope to offer a summarizing essay on “The Lessons of History.” (May 1, 1967)
Elude the Reaper they did, and a year later their essay came out as a book of a little more than a hundred pages, short by Durantian standards. That year, 1968, they were award the Pulitzer Prize for General Non-Fiction. And yet they undertook to produce yet another addition to their “integral history.” The Age of Napoleon is proof that they could not resist “sinning at such length again.” They justified adding to the vast literature on Napoleon by confessing
that the Reaper repeatedly overlooked us, and left us to passive living and passive reading after 1968. We grew weary of this insipid and unaccustomed leisure. To give our days some purpose and program we decided to apply to the age of Napoleon (1789-1815) our favorite method of integral history—weaving into one narrative all memorable aspects of European civilization in those twenty-seven years. . . . This vision roused us from our septua-octo-genarian lassitude to a reckless resolve to turn our amateur scholarship to picturing that exciting and eventful age as a living whole. . . . So here it is, a labor of five years, needing a lifetime; a book too long in total, too short and inadequate in every part; only the fear of that lurking Reaper made us call a halt. (1975)
President Gerald Ford hung the Presidential Medal of Freedom on the Durants’ shoulders two years later. On October 25, 1981, Ariel Durant died at the age of 83; their children tried to keep news of her passing from their father, but he managed to learn of it from the evening news. That was all “the Reaper” needed.
Not quite two weeks later, on November 7th, heart failure took him. Just before that, interestingly, the Catholic Church that had excommunicated this famous skeptic performed last rites for him. Who arranged that?