ONE FINE DAY - our descendants will look back at how we lived in 2021, and will be amazed. To read the 1972 Shelter Island-made, “Seafood Recipes from Local Waters,” by Jacqueline Pell Tuttle, is to experience that kind of astonishment.

It’s time traveling back to a place where the local waters held an incredible variety of fish, and the most economical and healthy way to put food on the table was to go down to the creek and haul it out. It’s a cookbook for every local fish you’ve ever cooked, several you haven’t, and a soberingly long list of aquatic foods that are no longer common in these parts.

Jacqueline Pell Tuttle’s family ran Pell’s fish market in Greenport in the 1950s and 60s. She wrote the book in part to help customers who were not sure what to do with a large live crustacean, or how to make dinner out of a few pounds of scallop meat. A home economics teacher for 40 years, she knew her way around a kitchen, and wanted to preserve some of the old-time recipes that everyone loved to eat, but nobody had bothered to write down.

I discovered this masterpiece when Terry Lucas, director of the Shelter Island Library, clued me in a few weeks ago. The book she lent me was signed by the author and marked “Property of Janet Badger,” so it may have been donated to the library by the Badger family. Ms. Tuttle confirmed that Janet Badger was a good friend, and although she doesn’t remember signing the book almost 50 years ago, she probably did.

I found out later there’s a copy at the Shelter Island Historical Society, but I’ve been clinging to this one like a blue crab on the bait, until I get one I ordered from an antiquarian bookseller.

If the importance of a thing is related to the number of words commonly used to describe it, then clams were the center of life on Shelter Island in the middle of the last century. Tuttle’s book opens with an extensive discussion of the seven or eight different kinds and sizes, the best use for each, and recipes such as soft clam pie contributed by Fanny Dickerson.

The recipe called “Tink’s Clambake” calls for half a bushel of clams, and had me down in the basement trying to see if I could unearth a “washboiler,” once I figure out what that is.

Equally earth-moving are the clam-cooking techniques Tuttle describes, such as separating the belly and grinding the tougher ridge part of a soft clam so it can be used with no hint of rubberiness. Here I was thinking that a clam was more or less a single thing, and I find out that you can (and should) butcher a large clam like you’d cut up a chicken for frying.

Mind blown.

The book is full of poignant reminders of what we have lost from local waters. There are 26 recipes with scallops as a main ingredient, more than any other seafood. In 1970, Shelter Island baymen harvested 28,000 bushels of bay scallops; by 1985 it was down to 7,421, and after recovering somewhat in the 2010s, the past two years have seen almost none.

On the night I spoke to Ms. Tuttle, she had just made one of her favorite recipes, “Baked Scallops Supreme” with a pound of delicious, but undersized and expensive bay scallops, and was so grateful to find them in Sawyer Clark’s roadside cooler that she bought two bags.

“There are not as many fish in the sea as there used to be,” she said.

Nowadays, mussels are mainly farmed out of state, but in 1972, Ms. Tuttle wrote, “The blue black mussel grows abundantly on the edges of many of our creeks. They are really delicious to eat and a very economical buy. The meat is a creamy golden-yellow so tender it melts in your mouth and as sweet as the smallest clams.”

The book also reflects the receding population of local lobster, driven north by warming waters, “…some of the largest lobsters weighing 20 pounds or more that have been taken in recent years have come from deep waters at some distance from land.”

Instructions for assessing the health of a live lobster and the quality of a cooked one, impress upon the reader that, no matter where the creature comes from, some fundamental lobster rules apply, “The tail should curl under the body and not hang down when a live lobster is picked up … the tail of a cooked lobster should spring back quickly after it has been straightened.”

Some recipes reflect food trends of the time. The 70s craze for Asian-inspired recipes resulted in “Shrimp and Apricots” a dish she describes as having, “a Chinese aura, but to my best knowledge it originated in a country kitchen.”

The aura came from ingredients like dried apricots, soy sauce and ginger, and the recipe likely came from the late food writer and Shelter Islander Jules Bond, who contributed several to the book.

Like all cookbooks of that era, this one has a gelatin-enhanced salad. Ms. Tuttle’s recipe for “Molded Seafood Salad” coheres cans of shrimp and crabmeat with mayonnaise and canned tuna into a shapely centerpiece for a festive table.

“Seafood Recipes from Local Waters” was a true community cookbook, illustrated with drawings by Amy Binder, printed and bound by David Binder’s Bliss Press, with recipes from baymen for local delicacies that otherwise might be lost, such as Capt. Edward Orr’s instructions for fried eels and a recipe from Capt. Ed Clark Jr. for potted mackerel.

“My grandmother used to fix mackerel that way and she was 50 when I was born,” Ms. Tuttle said.

And since time traveling is the only kind I’m allowed for now, I think I’ll pot up some mackerel, and roll out the pastry for a soft clam pie until we’re all vaccinated. At least we’ll be well-fed.

See you in the last century.