As a young nerd growing up, I used to love to read field guides. I owned field guides to insects, snakes, wildflowers, Hawaiian tropical fish, and North American songbirds. I had a collection of breed encyclopedias as well, including several on dogs, horses, and cats - wild and domestic. I loved the books' floppy faux-leather covers and the rows of glossy photographs, but what I really loved were the names.

Imagination is overrated - give me Latin classification any day!

It's a miracle I had any friends.

In high school biology, I remember learning about taxonomy, the science of classifying organisms, and how my teacher stressed the importance of proper nomenclature. Taxonomists estimate we've cataloged about 2 million species of animals so far, but that 3 million to 100 million more species are yet to be discovered.

Similarly, there are 8 million people in New York City, roughly half of them men. And I've only discovered about . . . well, that's private. The point is that well-organized classification is the first step to understanding. So I carry my field guide in my pocket every day:

My cell phone contacts list.

My contacts list has its own system of nomenclature. When I meet a guy in the field, so to speak, I don't always learn his last name. That's not as sketchy as it sounds, if you think about it. It would be weird if we all introduced ourselves with our full name. It worked for James Bond, but so did wearing a tuxedo every day.

I feel awkward asking a man I just met for his last name. It screams, "I'm going to Google you later."

I prefer to be discreet with my stalking.

Researchers in the field frequently work with limited information, but still, everything must be recorded. So I've developed a method of classification for these instances. I'm scanning my phone right now for an example - aha!

Aaron McManus.

Looks like an ordinary name, right? But to my studied eye, I know that that entry is "Aaron," a guy I met at "McManus," a local pub.

The formula is: First Name, Location of Discovery.

Entries like this are sprinkled throughout my contacts, forming a little scavenger hunt through my usual haunts.

There's Tony Pomme Frites, which sounds like a French mobster, but, in fact, Pomme Frites is a restaurant that sells only fries and is open until 3:30 a.m. on weekends. I recall that he complimented my shoes, we talked in the endless line, and I never saw him again.

Fries are bad for you anyway.

I also see the recently added John Grassroots. Grassroots is a bar in the East Village. We met on a Friday, he called me on Monday, and I'm excited to see him Thursday!

Mr. Grassroots has potential. If we have a nice time on Thursday and I see him again, then he can earn a proper classification. But if it doesn't pan out, he'll languish in my contacts list, sandwiched between layers of G last names, frozen in time with the cute smile and the Ray-Bans tucked on his shirt collar.

A Contact Fossil.

My system is mainly designed to help me remember people when I pick up the phone, but sometimes it reminds me when not to pick up. A few examples:

Lucky Never. This guy works for my building management company, but that didn't stop him from hitting on me outside my apartment. After I'd introduced myself, he actually winked and said, "You can call me Lucky." I smiled, but what I wanted to say was, "You can call me never." Hence, his entry.

Roy Old Rusty Knot. Sadly, the name of the bar is only Rusty Knot. I feel a little bit bad about that one, but really, he was my father's age.

Creeper Noah. Ah, this is a special naming case. Normally, the first name is the most important information, but when it comes to creeps, the warning factor takes precedence. Also in my phone:

Creeper Josh.

Creepy Exterminator.

Unfortunately, my section C is packed.

Thank you, New York.

Look for a collection of Lisa and Francesca's columns in "My Nest Isn't Empty, It Just Has More Closet Space" and "Why My Third Husband Will Be a Dog." Lisa's new novel, "Save Me," is in stores now. To contact Francesca, visit francescaserritella.com