Infamous failures of large engineering structures -- like the Tacoma-Narrows Bridge, the Teton Dam or the Hyatt Regency skywalks -- are catastrophes that no one wants to see repeated. Thus it seemed fitting to close a recent article explaining how such failures can occur with a paraphrase of Santayana's familiar dictum about those not remembering the past being condemned to repeat it.

Little did I realize that some reader would challenge Santayana's words, or at least their provenance, and point out to me that the familiar quotation is not in "Bartlett's." He suggested that one of his ancestors might have first uttered the pithy saying. This sent me on a scholarly adventure that was to demonstrate to me that humanists, like engineers, are human.

I did find Santayana's familiar words in "The Reader's Digest Treasury of Modern Quotations," along with another nice Santayana quote about welcoming the future. But the sources are given only as "George Santayana, as quoted in Reader's Digest." This was a little too insular for me, so I copied down the issue dates and descended into the library's sub-basement.

I began to suspect an Orwellian conspiracy when I found the pertinent pages of "Quotable Quotes" neatly excised from the bound volumes of Reader's Digest. Were those voids soon to be filled with tipped-in pages quoting the big brother of someone with a razor blade?

Determined to prevent the rewriting of history, I immediately looked through every book of quotations I could lay my hands on, before somebody else did. In the last one on the shelf, "The Oxford Dictionary of Quotations," I found: "Those who cannot remember the past are condemned to fulfil it."

Fulfil? Why, this was as fantastic a discovery as finding an uncatalogued folio of Shakespeare among the atlases. I would look up the reference to Santayana's "The Life of Reason" and explicate the long- misquoted text. How ironic, I thought, that those who had not remembered the passage will be condemned to reread it.

My library, it turns out, has not the first (1905) edition of "The Life of Reason" but the second (1924). And it reads not "fulfil" but the pedestrian "repeat." Now I was even more excited. No doubt Santayana had revised the word from edition to edition, and now I would be able to expound at length upon his change of heart during the great World War.

On a steamy Saturday, on a hunch, I descended into the book mines of the university library in Chapel Hill. In the labyrinthine stacks to where no football cheers can penetrate, I found what I imagined to be the last extant first edition of "The Life of Reason." I quickly turned to page 284 in Volume One and read: "Progress, far from consisting in change, depends on retentiveness. . . . Those who cannot remember the past are condemned to repeat it."

I cursed Oxford for misleading me, and yet I thanked it for reminding me. The details, oh, the details. Why is it that we do not check them more carefully? For they can send innocent readers into the bowels of libraries, where madmen mug books, and they can send innocent citizens to their deaths in cracked airplanes and on shaky skywalks. In an engineering design office or at a construction site, a single miscopied number or cracked part can jeopardize an entire structure.

Nothing can erase engineering disasters, but they need not be repeated. By talking about them we learn from them, and by learning from them we obviate their recurrence. As Santayana also said, if Reader's Digest has quoted him correctly, "We must welcome the future, remembering that soon it will be the past; and we must respect the past, knowing that once it was all that was humanly possible."

The writer is director of graduate studies in civil and environmental engineering at Duke University.