Books are as seasonal as shoes, even if you’re a pool-phobic, sand-suspicious urbanite whose ideal hot-weather outing is lunch on Beach Street in Tribeca. Lightweight novels are of course the summer norm: the strappy sandals of literature. But they’re not the whole story. A month or so of fluff brings on a craving for substance—sentences to nourish the soul and perk up the lazy mind.

How to pick the big book to pack along with the easy reads? Whether you’re browsing online or in a bookshop, catching up on classics or taking a chance on the new, there’s a method as smart as it’s simple. Open to page one. Read line two. Yes, line two. Brief or convoluted, the second line of a novel is the real introduction.

After all—anyone can write a first line. And nearly everyone has. “Howard Roark laughed.” “Call me Ishmael.” “Happy families are all alike . . . .”

Such first lines are iconic, even among those who haven’t read the novels to which they’re attached. Critics perennially rank them. Literary barflies swap them at 2 a.m.

The first line is a nice place to start. The second line speaks volumes—is, indeed, a bridge to its volume. Without a second line, how would any book ever get to where it’s going? The first line is merely a tollbooth. Drive around it.

“Howard Roark laughed.” Read it aloud and you’re right there at the quarry, chewing gravel. Spit it out and move on to the second line: “He stood naked at the edge of a cliff.” Suddenly, you’re in Eden—the only place to start. Especially on a hot summer day.

Here are 21 great second lines from 21 first-rate reads:

Watch out for life.  KURT VONNEGUT, Deadeye Dick

I write these pages at some point in the time of Richard Nixon’s unravelling.  JOHN UPDIKE, A Month of Sundays

He would be the first pedestrian of the day.  JOYCE CAROL OATES, The Falls

My sin, my soul.  VLADIMIR NABOKOV, Lolita

“It’s so dreadful to be poor!” sighed Meg, looking down at her old dress.  LOUISA MAY ALCOTT, Little Women

The first time Yossarian saw the chaplain he fell madly in love with him.  JOSEPH HELLER, Catch-22

The cold outside my window reminds me of the cold emanating from my own body.  HENNING MANKELL, Italian Shoes

All my life I had been looking for something, and everywhere I turned someone tried to tell me what it was.  RALPH ELLISON, Invisible Man

The parking lot attendant had brought the car out and he was still holding the door open because Terry Lennox’s left foot was still dangling outside, as if he had forgotten he had one.  RAYMOND CHANDLER, The Long Goodbye

For a while we felt rich and then we didn’t.  JOAN DIDION, The Last Thing He Wanted

Or yesterday maybe, I don’t know.  ALBERT CAMUS, The Stranger

Specialized readers may have come across me in Dr. Peter Luce’s study, “Gender Identity in 5-Alpha-Reductase Pseudohermaphrodites,” published in the Journal of Pediatric Endocrinology in 1975.  JEFFREY EUGENIDES, Middlesex

A brisk little breeze had impudently slipped into the bedroom.  FRANCOISE SAGAN, That Mad Ache (La Chamade)

Liberty wore a mobcap and carried a pike.  JOHN CHEEVER,  Falconer

An alarm clock clanged in the dark and silent room.  RICHARD WRIGHT, Native Son

When the day came for me to leave the hospital, I barely knew how to walk anymore, could barely remember who I was supposed to be.  PAUL AUSTER, Oracle Night

She was small and blonde, and whether you looked at her face or at her body in powder-blue sports clothes, the result was satisfactory.  DASHIELL HAMMETT, The Thin Man

It’s not clear to him when exactly he became conscious, nor does it seem relevant.  IAN McEWAN, Saturday

I’m stupid about executions.  SYLVIA PLATH, The Bell Jar

“Too much fat,” Paul says, carrying in dishes from the dining room.  A.M. HOMES, Music for Torching

It begins.  LAWRENCE DURRELL, The Black Book

This is Nancy Weber and Ellen Stern’s second double byline for NYCitywoman. They believe in second chances, second thoughts, second helpings, and, of course, second children. But not the Second Avenue subway.