Readers who insist on visiting the beach this summer — there is really nothing to see except sand and water, but I digress — need to make some fundamental decisions not just about what they want to read while dry-roasting themselves in the sun (new John Grisham vs. new Toni Morrison) but about how (e-reader device vs. Gutenberg device).

That we even need to contemplate Beach Content Delivery Systems (BCDS) speaks to the world in which we now live, with 21 percent of Americans reading at least one e-book a year, according to Pew Research. Conversations about books these days invariably turn to how we read them, a transformation of our intellectual life that would probably make Gutenberg toss up his Bible in despair.

So how should we read at the beach?

The question is not as cut-and-dried as other beach decisions, such as “Would I be more comfortable at the beach just sitting in the car with the AC on high?” With beach reading, if you are going to abandon print, then you have to decide among the Kindle, Nook, iPad or other competing device. Let me help.

There are no book covers on e-readers, meaning you can read all the steamy sex you want and tell your friends that you’re reading the new Robert Caro. This is one of the key advantages to e-readers — lying about your reading habits — and it probably helps explain why guilty-pleasure fiction is the most popular genre of reading on e-readers, according to the Book Industry Study Group. (I had to ask my wife last month whether she was reading “Fifty Shades of Grey” on her e-reader. Yes, she was.)

Seaside e-reader use. (Marco Cibola for The Washington Post)

Another advantage to e-readers at the beach is that they weigh less than a paperback, and you can fit thousands of books on them without adding a single ounce, which is basically a miracle. If you are already packing kids, their gear, food, towels, luggage filled with clothes, the dog, the dog’s gear, bikes, rafts, coolers, a barbecue, your briefcase (ha-ha), an inflatable bed and a watermelon from a farmers market on the way out of town, being able to carry a tiny device instead of seven or eight heavy books will be the best part of your beach vacation besides going home.

So now the question becomes: Which e-reader?

We need to break these down into two categories: tablets and e-ink readers.

Tablets like the iPad (starting at $399), Kindle Fire ($199) and Nook Color ($169) are generally wonderful and transformative machines. The new iPad (starting at $499), with its retina screen, provides an amazing reading experience. There are more pixels in that thing than the best high-definition television, and if my house caught fire, I would make sure I had it on the way out the door.

But tablet screens are backlit and subject to glare, which makes reading them outdoors, especially in bright sunlight, nearly impossible. Actix, a mobile analytics firm, reports that 95 percent of iPad use is indoors, which means either that iPad users hate the sun or the sun hates the iPad. Despite my bias against the sun, I think it’s the latter. If you’re going to be under an umbrella — or in the car — a tablet like the iPad might work. But it will be tricky to read on it at length.

E-readers like Amazon’s Kindle (starting at $79) and Barnes & Noble’s Nook Simple Touch ($99) use e-ink, which mimics how text appears on the printed page. E-ink screens work just fine in the sun, with little, if any, glare. There is no color, but the text appears dark and rich. Despite my love for the iPad, I prefer reading books on my Kindle because of the way the device imitates the look of paper.

The long-standing downside to e-ink screens is that they can’t be read in the dark without a flashlight. But Barnes & Noble recently solved this quandary with its new Simple Touch with GlowLight ($139), which features an e-ink screen capable of lighting up in the dark. Let it be said that summer 2012 is officially the first summer when you can comfortably read an e-reader at night on the beach without the moon’s help. This is called progress.

A few tips: If you don’t have a cellular data connection on your e-reader, be sure to download books over WiFi before leaving for the beach. Also, pick up a decent case — sand and electronics are not best friends. I shouldn’t have to point this out, but I will: You might be able to continue reading from a printed book that accidentally takes a dip in the ocean, but a waterlogged e-reader is as unusable as an empty tube of suntan oil.

Last tip: Reading on the couch is a lot more comfortable than reading on sand.

Rosenwald is a writer for The Post.