One of our culture’s great sources of serendipity, Brewer’s Dictionary of Phrase & Fable,” defines “serendipity “ as “a happy coinage by Horace Walpole to denote the faculty of making lucky and unexpected ‘finds’ by accident … he formed it on the title of a fairy story, ‘The Princes of Serendip,’ because the princes ‘were always making discoveries, by accident and sagacity,’ of things they were in quest of.” For good measure, Brewer’s adds that “‘Serendip’ is an ancient name of Ceylon (modern Sri Lanka).”

Our country’s public libraries top even Brewer’s for serendipity, offering not only a wider scope of things to consider, but also a depth that Brewer’s can’t approach. This attribute is further enhanced by our public libraries’ open shelves. Visitors can wander at will through the aisles of bookshelves, DVDs, magazines, audio books, video games, music CDs and other collections, viewing useful and amusing things they didn’t know they wanted. Americans take libraries’ open shelves for granted, but just try to find a library that allows it in other lands.

Don’t overlook Walpole’s point that discovering things serendipitously involves sagacity as well as luck. Allowing one’s curiosity freedom to roam a well-stocked library requires the good fortune to live near one, but being intellectually active is a necessary precursor. Most Americans are lucky and have the run of their public libraries, which provide the means to learn nearly anything they want, and things they didn’t know they wanted, and statistics show that most of them utilize their libraries.

It helps to possess an easily aroused sense of curiosity. A recent Osher Lifelong Learning class taught by Susan Stitham reminded me how often serendipity guides my personal reading. The course was on Shakespeare’s Richard and Henry plays, and Susan remarked that Geoffrey Chaucer was the brother-in-law of Richard II’s uncle, John of Gaunt. Shakespeare painted Richard as an effete, prancing fellow who listened to wretched advisors.

Susan’s comment reminded me about “Who Murdered Chaucer” by Terry Jones, whose book is rigorously scholarly, belying his roots with Monty Python. Jones builds a strong case for Chaucer’s being assassinated due to his close connections with King Richard. He further shows how Richard was trying to centralize the power of the monarchy, how unpopular this was with the nearly-autonomous English barons, and their success in skewing the historical record to reflect their desired spin.

The path to Jones’ book began with a graphic novel version of “Canterbury Tales” that inspired me to compare one of its tales with a translation from Chaucer’s Middle English that I owned. Then I decided to contrast that with a more recent and engaging translation. Decades ago, I’d read Barbara Tuchman’s “A Distant Mirror: the Calamitous 14th Century,” and recalled her description of the utter bleakness of 14th-century childhood during that most horrible of centuries. I wondered how Chaucer, a child of the 1300s, could write such light-hearted tales in such desperate times. Turns out that Tuchman’s views on childhood are roundly disputed in Donald Howard’s “Chaucer: His Life, His Works, His World.” Several related books later I came to “Who Murdered Chaucer.”

This is a well-trod path for me. My encounter with “George Washington’s War” by Bruce Chadwick, led to a book on Washington’s spy-ring, biographies on Lafayette and Robert Rogers, Michael Stephenson’s “Patriot Battles: How the War of Independence Was Fought,” and others.

A gift of Sarah Bakewell’s excellent “How to Live, or A Life of Montaigne,” has led through several translations of Michel Montaigne’s “Essays,” including that of Shakespeare’s contemporary, John Folio, who made Montaigne’s works resound to English ears, a century later influencing Laurence Sterne’s strange, idiosyncratic masterpiece, “Tristram Shandy,” which is more readable when understood to be a tribute to Montaigne, whose essays rank among the most free-wheeling, open-hearted, and, yes, serendipitous writings ever.

It goes on and on. “Curiosity,” as author and columnist Arnold Edinborough noted, “is the very basis of education, and if you tell me that curiosity killed the cat, I say only that the cat died nobly.”