WASHINGTON—I arrived late to the book party launching Maggie Hall’s new book about Marmite, an English condiment that is perhaps the foulest compound legally sold for human consumption. Late, but not late enough: There was still plenty of Marmite left.

Like Marmite, Maggie is English. Unlike Marmite, I like Maggie. A former reporter for Britain’s Daily Mirror tabloid newspaper—“horror, sex, scandal,” is what she says she wrote about—she’s 68 and lives with her American husband, Gary Humfelt, in Washington. Her book is titled “The Mish-Mash Dictionary of Marmite: An Anecdotal A-Z of ‘Tar-in-a-Jar’ ” (Revel Barker, $15).

How to describe Marmite, a foodstuff that, like warm beer and rainy summers, informs the English national identity? Imagine putting hundreds of anchovies in a blender, adding salt and axle grease, then pureeing until you have a black, gooey precipitate. That is Marmite.

That’s how it tastes, anyway. What it IS is yeast extract. You might wonder why someone first thought to extract something edible from yeast. I know I did. Apparently when you brew beer, there’s all this sludge left over. Using science, you can make Marmite out of it. Also Vegemite, which is the Australian version of Marmite name-checked by the group Men at Work.

This is all in Maggie’s little book, its entries arranged alphabetically. Under “vitamins,” you learn that Marmite is packed with thiamine, riboflavin, niacin and folic acid; under “fishing,” that some anglers think it attracts catfish and carp; under “museum,” that a Missouri man has a shrine to Marmite in his basement and under “outer space,” that Yorkshire-born NASA astronaut Nicholas Patrick brought Marmite with him as his “comfort food” on a 2006 space shuttle mission. (It would also have been handy for patching damaged thermal tiles.)

Marmite’s manufacturer, Unilever, admits it’s an acquired taste. The admirably honest slogan: “You either love it or hate it.”

Maggie loves it.

“I’ve liked anchovies from the age of 18 months,” she said, “so what can you say?”

At Maggie’s book party, there were the tiny yellow-lidded jars of Marmite that you can sometimes find in American supermarkets as well as big jars weighing a pound that Maggie brought back after her last trip home to England. A Marmite-inspired smorgasbord had been laid out. There was Marmite egg salad, Marmite-infused sausages, Marmite and marmalade sponge cake. You could get a Bloody Mary seasoned with Marmite.

The traditional way to consume Marmite is to butter a piece of toast and then spread a thin layer of the dark goo on it. A very thin layer.

That’s what I tried to do, anyway. My toast carefully Marmited, I took a bite and immediately felt as if I’d been hit in the face by an ocean wave, a wave befouled by oil from a sinking tanker, oil that had caused a die-off of marine birds and invertebrates, creatures whose decomposing bodies were adding to the general funkiness that had found its way inside my mouth.

The refreshment table also had pumpkin bread.

“That’s the only good thing in here,” counseled Gary. “There’s no Marmite in it.”