That’s how I felt about Jon Krakauer’s “Under the Banner of Heaven,” a thick paperback I picked up, half-price, at a college bookstore. (The book I’d brought for the trip, Howard Norman’s “What is Left the Daughter,” was so bad I left it on the airplane. Plodding, predictable: curses on the reviewer who sent me to it!)

So there I was in the newly green Philadelphia suburbs without a book.

Their yard sale; my salvation.

How to describe this read? It’s not a straightforward survival tale, like his earlier books, “Into the Wild,” and “Into Thin Air.” Extreme behavior is their common thread, but this book is longer, richer, messier. Its footnotes could be a separate read.

“Under the Banner of Heaven” (2003) begins with the brutal death of a young mother and her child in 1984, then turns back and recounts the remarkable and often violent early days of the Mormon Church, beginning in 1830. How the one is linked to the other is, eventually, entirely logical.

Warning: this is not a fluid read. Back and forth and up and down North America, at least two dozen people’s stories color this book. I was never bored, but these real-life characters blend into each other.

Memorable: prophet and founder Joseph Smith, the brothers who murder, the woman and child they slaughter.

Throughout, I was astonished and disgusted by Krakauer’s descriptions of men’s actions in the name of God: polygamy, pedophile, rape, incest, swindling, kidnapping, racism, terror, murder.

If God instructed these men to murder, can they be held accountable? Are they fit to stand trial? Are all believers crazy?

An uncomfortable read. Fascinating history.

In between: I read.

I read small books and big books, fiction and nonfiction, old books and those newly published. I read for hours at a time. If it’s hot, I strip down to my swim suit. surface dive into the black water, take a few strokes, float …and go straight back to my chair and my open book.

I guess that’s nothing to a ten year old. To me, it’s bliss. To read a “big” book without interruption, in the sun, beside a clear water lake.

Recently, these have been my favorite “big” reads, all consumed on that dock:

• Titan: The Life of John D. Rockefeller, Sr. by Ron Chernow, Vintage, $18.95. Sounds forbidding — and is, at 832 pages — but this is one of the most intimate biographies you’ll ever read. I learned more about U.S. business than from any text. Sounds dry? It’s not. A big life, a grand read.

• The Looming Tower: Al Qaeda and the Road to 9/11, by Lawrence Wright, Vintage, $17. Want to know how Al Qaeda began? I did. Wright is a gifted storyteller, and his research astonishes. I even read the endnotes. A friend tried to read this going to and from work on the bus. Impossible. It is a complex read, and we know the ending. This one deserves your full attention.

• A Star Called Henry, by Roddy Doyle, Penguin, $15. A few pages into this epic, Greitja Morse stopped by the dock. “Ohhh,” she said knowingly, as though speaking of a former lover. “Doyle is so hard to give up.” Henry Smart comes of age, and plays a part, in the Irish Rebellion. A rollicking read. Doyle’s masterpiece.

• The Brief Wondrous Life of Oscar Wao, by Junot Diaz, Riverhead Trade, $14. My then 18 year-old-son read this in a single day on the dock, then slammed it down: “This should be taught in every U.S. high school.” A 21st century must-read, about Dominicans in the U.S. and back home. End is perfect, brutal, heart wrenching.