The oldest known fully preserved garment is a shirt that dates to Egypt, circa 3000 BC. Which is another way of saying that Egyptians cotton is solid. Same goes for Pima and Sea Island. All three varieties come from the same type of plant, the Gossypium Barbadense, whose long fibers make fine, strong threads.

Thread count refers to the number of threads per square inch in a piece of fabric. The higher the number, the smoother, silkier, and pricier the fabric.

A shirt that’s made from two-ply fabric does not actually have two layers, like the roll of two-ply paper towels hanging in your kitchen. Two-ply fabric is what you get when two yarns are intertwined into one before being woven. The resulting fabric is stronger and more luxurious than single-ply.

Know your weaves: Broadcloth is a tight weave, which is dressier and often has a slight sheen. Twill is softer than broadcloth and drapes more easily, with a diagonal texture that shows off stripes and patterns nicely. Oxford cloth is made with a basket weave, and as such is heavier and commensurately less formal.  

What we know as the dress shirt was popularized by Beau Brummel, who advocated a kind of English dress based on honest military and agrarian tailoring (as in, shirts without ruffles) in the early 1800s. This was a reaction against the flowery look of French aristocratic fashion, and is somewhat ironic given Brummel’s rep as the ur-dandy.

Cuffs are a chief signifier of formality. Here’s the range, in order of formality, from less to most: single-button barrel, two-button barrel, and French. Cuff ends come three ways: square, round or mitred (i.e., cut at a 45-degree angle.) Some contend that a mitred edge makes a barrel cuff a tad dressier. Whatever shape you choose, your cuffs should fit tightly enough on the wrist that you can’t get your hand through them when fastened.

To keep your collar erect—as it ought to be—metal collar stays tend to work best.

A fused collar or cuff (the most common type) is one in which the interlining is attached, via adhesive, to one of the outer layers. Purists tend to prefer non-fused collars and cuffs, but the technique, if done properly, is an efficient way of providing stiffness. Rub a cuff between your thumb and forefinger: if one side moves a little, and one side not at all, it’s fused; if both sides move, with what feels like a floating piece of material between them, it isn’t. For reasons unknown, the Italians seem to favor fusing, while the English do not. As in many areas of sartorial debate, neither is right. 

There are some widely held guidelines as to what collar goes with what face type. To wit, gents with square faces are supposed to opt for narrower, more pointed collars to help elongate their mugs, while longer faces are, theoretically, balanced by a spread collar. As with all rules of style, these are made to be broken. Wear what you like.

And now for some useful conventional wisdom: Your collar should be high enough to protrude about half an inch above the collar of a suit jacket. If you wear your shirt with a tie, the collar’s points should still be able to touch the shirt’s front with the tie fastened.

The club collar, which is defined by its rounded edges, drifts in and out of fashion every seven to eight decades. Now happens to be one of the times when it’s in vogue. The club collar is a great look, but, thanks to its old-timey flavor, we advise against pairing it with waistcoat. Unless, of course, you work in a Prohibition-themed cocktail bar in Brooklyn, in which case you should be shopping for one.

Brooks Brothers introduced the button-down collar in 1896 (note that it’s the type of collar, and not the fact that a shirt has buttons on the front, that makes a shirt a “button down”). Depending on whom you believe, owner John E. Brooks took inspiration from the tied-down collars of polo players, or because he became frustrated when his collar flapped in his face when he was next to the river one windy day. Either way, one thing’s for certain: dude did not like floppy collars. 

The British phrase “to get shirty” means to become annoyed or irritable. It comes from the phrase “to have one’s shirt out,” meaning that, when a person is in a fist-raising rage, their shirt will become untucked.

Mother of pearl comes from the inside of an oyster shell. It’s stronger than plastic, but also more likely to degrade after repeated encounters with laundry detergent.

The placket is a strip of fabric, raised off the shirt, which holds the buttonholes. A cleaner and dressier look is the so-called French placket, which is barely a placket at all: the edge of the shirt is folded over, creating a creased edge that is held in place by the buttonholes. There is also the covered placket, which is, well, pretty much what you think.

Single-needle stitching produces a single row of stitches at the seams (which involves one needle going over the same area twice), as opposed to the two parallel rows you get with double stitching. Single needle seams are significantly less prone to puckering, and many people consider them to be stronger. 

The gusset is the triangular piece of fabric at the bottom of the side seam, which is designed to add strength and flexibility.

Okay, let’s talk fit. A shirt can be made of the finest Sea Island cotton, hand-stitched by Italian artisans in some idyllic hilltop town, but it’s not worth much if it doesn’t fit properly. Avoid the blousy, tented look at all costs: There should be little or no fabric billowing above your waistband when the shirt is tucked in, and no danger of a breeze inflating the front when it’s untucked. You don’t want your shirt tight enough for strangers to count your chest hairs, but it should closely follow the shape of your torso, while still allowing you to cross your arms without it pulling at the shoulder.

And now let’s talk sleeve length: With your arm at your side and your shirt cuff buttoned, you should just be able to brush the tip of your shirt sleeve with your middle finger folded back against your palm. Additionally, you should be able to stretch your arms out without the sleeve traveling more than a half-inch up your wrist.

As you’ll recall, in The Great Gatsby Daisy is reduced to tears by the beauty of Gatsby’s shirt collection. Admittedly, there may have been some extenuating circumstances behind Ms. Buchanan’s waterworks, but still: When it comes to one's shirt wardrobe, engendering the same reaction is a worthy goal to aspire to.