On this 150th anniversary of Beatrix Potter's birth, I count myself lucky to have met a handful of people who knew her in her later years, when she was most decidedly not Beatrix Potter, but Mrs. William Heelis. By the time she married at age 47, she was beginning to put the "little books" behind her and concentrate on her third act, which was a great deal happier and more fulfilling than the first act (stuffy London childhood). I also consider myself lucky to work here at the Horn Book where, some years ago, I had the chance to hold in my hands and read pages and pages of letters Potter wrote to Bertha Mahony Miller, our intrepid founder.

Virtually every quote you will ever read in which Beatrix Potter mentions her childhood, her influences, or creating her books can be found in those letters. Somehow, Bertha persuaded her to stop being an old crank who refused to be interviewed or to write about herself. Beatrix even wrote some articles about her books for The Horn Book. After her death in December 1943, Bertha wrote "Beatrix Potter in Letters," a tribute that proved how forthcoming Mrs. Heelis had become about her little books.

At some point, Beatrix even filled out this author information form for one of the Horn Book's other publications:

In case you can't read the handwriting, here's what she wrote at the bottom:

As Americans on tour inspect every corner of old England — as country cousins on holiday are better acquainted with the sights of London than any native Londoner — so it sometimes happens that the town child is more alive to the fresh beauty of the country than a child who is country born.

My brother and I were born in London because my father was a lawyer there. But our descent — our interests and our joy was in the north country. It is immaterial to give the address of my unloved birthplace. It was hit by shrapnel in the last war; now I am rather pleased to hear it is no more!

So how will you celebrate Potter's birthday? Myself, I plan to sip camomile tea while watching my DVD of Miss Potter starring Renée Zellweger. As you might expect, this 2007 biopic concentrates on BP's second act — the Peter Rabbit years — and has some cringeworthy moments. It also has beautiful cinematography AND Ewan McGregor as Norman Warne, her first editor and love interest.

In a perfect world, I would be watching instead a movie called Mrs. Heelis starring Judi Dench. It would begin with an aerial view of the Lake District, gradually zooming in on a middle-aged woman trudging up a muddy country road. She is dressed in shapeless tweeds made from her own sheep's wool. The plot: at first, the cast of colorful locals will be suspicious of the rich lady from London who bought Hill Top Farm at twice its actual value. But soon William Heelis, a local lawyer and athlete, will fall in love with her and they will marry. Did I mention that he is tall, kind, handsome, and five years younger than she? Mrs. Heelis buys more and more farms and becomes a landlady and sheep breeder, using her knowledge of animal anatomy to help her choose the best rams. Soon she is participating in local affairs, winning ribbons for her sheep, and supporting the Girl Guides who enjoy camping trips to her woodlands. During the second half of the film, Beatrix will become an avid conservationist, campaigning to save thousands of acres from evil developers. The final scene will take place in a tavern where 75-year-old Beatrix will be elected the first woman president of the Herdwick Sheep Breeders Association by many of those same colorful locals who once despised her. All true.

Of course, that movie doesn't exist. But when I read Beatrix's letters to Bertha — or the later chapters of Linda Lear's excellent biography, Beatrix Potter: A Life in Nature, I like to imagine that it does.

There is much more Potter material I could share, but you'll have more fun if you discover it for yourself. I promise, the more you read about this remarkable woman, the more you will admire her.

In a few months, we will relaunch our Virtual History Museum on this website where you will be able to see three of Beatrix's letters to Bertha. In honor of today's 150th birthday, here is a VHE preview: an early illustrated nursery rhyme Beatrix sent to Bertha.