Kate Braestrup’s 2007 memoir, Here If You Need Me, was a moving, luminous, often riveting account of the author’s journey from finding herself a newly widowed mother of four to becoming an ordained minister and the chaplain of the Maine Warden Service. It sat comfortably on the New York Times bestseller list for weeks and left an indelible imprint on many readers.

Braestrup’s latest volume, Marriage, and Other Acts of Charity (Reagan Arthur Books, New York, NY; hardcover; 224 pages; $24.99), does not quite pick up where the earlier book left off, but rather weaves new patterns from the same threads. She revisits her first marriage, to Maine State Trooper Drew Griffith, and her second, to artist Simon Van Der Ven, peeking along the way into other lives and other relationships, mostly involving the Maine wardens with whom she works every day. In all these places she finds evidence of both the amazing human capacity to love and the vexatious human tendency to screw things up. And at bottom, always, she discovers divinity, transcendence, and grace.

Reading Braestrup is a bit of a roller-coaster ride. (Full disclosure: I know Kate Braestrup personally — she lives just down the road.) She is by turns funny, affecting, profound, irreverent, wise, and weird. She’s fond of quoting Scripture — often in ways that may strike the pious as impolite — but equally fond of quoting bumper stickers: “I Got A Dog For My Boyfriend, Best Trade I Ever Made.” Her relationship with the Christian Savior might best be described as chummy.

With Braestrup, there’s always more going on than meets the eye. Look again at that title. The word “charity” means what we think it means but also something larger. It comes to us from the Latin caritas, which in turn is equivalent to the Greek agape: a kind of love that is “wholehearted, impartial, and selfless.” This is the kind of love we’re enjoined by Jesus to feel for our neighbor. It doesn’t mean we have to like the guy. It means, as Braestrup puts it, “to earnestly desire the achievement of wholeness by the beloved.”

Which, in a nutshell, is what this book is about. Braestrup’s topic is marriage, but not marriage as an institution or a sacred bond or a cause of torment or a promising endeavor that doesn’t always pan out. (She shows it to be potentially all those things.) Instead, she regards it as a crucible, a test of our ability to demonstrate, through good times and bad, the deepest kind of love. How, she seems to ask, can we make marriage a true act of caritas, of agape?

Seeking an answer, we journey through the wilds of Maine. One memorable scene, involving a warden called Jesse, finds us “lying on our stomachs on a spice-scented bed of leaves in the middle of a forest . . . keeping watch over an illegal deer bait.” From this perspective we learn that porcupines mate for life, that Braestrup’s first marriage, “the one that taught me how to serve God,” nearly ended in divorce, and that she saved it by climbing out of bed at 3 a.m. to clean a fish tank. We also see some deer.

This is, in other words, a rather madcap book about very serious things set on a backdrop of Maine. It’s also pretty much fun to read — a seeming paradox that becomes more striking when you consider the terrible events it recalls (drownings, divorces, untimely deaths) and also that the author is, among other things, a woman of the cloth.

Braestrup takes her religious vocation seriously. She declares it up front — “I believe absolutely in God made manifest in love” — and it runs like a golden thread through the book’s many episodes and anecdotes and digressions. Yet when she speaks of Jesus, it’s in nearly the same wry, familiar tone she uses for her pals in the Warden Service.

Here’s an example. Braestrup tells the story, found in Matthew and in Mark, of Jesus causing a fig tree to wither. “My father,” she comments, “did odd things like this when his blood sugar was low.” Jesus goes on to tell the disciples that “if they have sufficient faith in their hearts, they, too, will be able to wither fig trees, or even chuck mountains into the sea, which, again, sounds less like a miracle and more like the sort of asinine thing Drew and I used to do in the midst of a marital dispute.”

If you’re new to Braestrup, you might start with the earlier volume before moving on to this one. But do start somewhere — this may be the most rewarding thing you’ll read this year.