I love it when I'm deep in a book and suddenly realize that it was inspired by one of the classics. Leif Enger's "Virgil Wander," for instance, is packed with subtle homages to a multitude of great books (inspired, he said in an interview, by the Classics Illustrated comic books he read as a child).

And Charles Baxter's "The Feast of Love" features an insomniac character who encounters all sorts of fascinating people on his nocturnal wanderings — "A Midsummer Night's Dream" moved to contemporary Michigan.

Why do writers do this? Sometimes the author sees a fresh way to tell an old story. Sometimes they want to explore how a period piece can be recast for modern times.

Sometimes they want to turn a book inside out and present a different perspective — such as Jean Rhys' "Wide Sargasso Sea," which tells the story of Mr. Rochester's first wife, the one who was hidden away in the attic in "Jane Eyre."

And sometimes it's just fun to see if characters and themes hold up when transported 100 years into the future.

But updating a beloved book is risky, especially when you're updating a book that people read in their youth. We have a lot of emotions tied up in those books, and we want writers to tread carefully.

Two beloved books from my childhood — "Little Women," by Louisa May Alcott, and "Anne of Green Gables," by L.M. Montgomery — have recently received updates with mixed results.

The "Anne books" were among my favorites when I was 13, a series that took the redheaded orphan from childhood to motherhood.

Brina Starler's modern-day retelling — "Anne of Manhattan," to be published June 1 — was a baffling disappointment. The names of the characters were the same, and Anne still had red hair, but there the similarities stopped. It's not that I expected the plot to duplicate the original, but this Anne's personality was nothing close to Montgomery's Anne; this Anne could have been anybody.

And, frankly, I hadn't been prepared for the graphic sex scenes. If your dreamy teenager loves Anne, you probably do not want to give them this book.

But the two modern-day "Little Women" retellings by Virginia Kantra ("Meg & Jo," 2019, and "Beth & Amy," out May 25) were a delightful surprise.

Told in first-person chapters with alternating narrators, both books felt as if the March sisters had seamlessly moved from the 19th century to the 21st. Clearly, Kantra thoroughly absorbed Alcott's book and was able to channel the characters' thoughts, fears, expectations and personalities.

The details of their lives were different, Prof. Bhaer was now a chef, not a teacher, but those things were immaterial; this was Meg, Jo, Beth and Amy on the page.

And in "Beth & Amy" Kantra did what no one has been able to do before, not even Alcott — she made me like Amy. (Even Greta Gerwig's much lauded 2019 movie version couldn't do that.) Here Amy's selfishness is revealed as hero worship of Jo and also as a burning need to be seen over the overwhelming personalities of her sisters. Her adoration of Laurie (called "Trey" here) feels right. (And this is coming from me, a woman whose name — Laurie Jo — married Laurie and Jo forever.)

So what was the difference between the modern-day Anne book and the modern-day March sisters books? Heart, I think. Fidelity to the characters, to who they were and what they stood for.

Mess with favorite books at your peril. If you get it wrong, readers will not forgive you. But if you get it right, you might create a modern classic. Perhaps in 100 years someone will be updating your novel.

Laurie Hertzel is the Star Tribune's senior editor for books. E-mail: books@startribune.com.