Do you remember your first time? For most of us, it was in a supermarket, and it was a strange and somewhat unsettling experience.

You gazed around and there were little black and white stickers on everything: milk jugs, packages of Oreos, boxes of laundry detergent. The stickers all looked similar, yet slightly different. But those differences that were so imperceptible to our untrained eyes apparently meant a whole lot to the Star Trek-esque laser things at the checkout counter.

We speak, of course, of the bar code. This summer marks the 30th birthday of the iconic symbol that has changed our lives, not to mention the logistics profession. Although they had been kicking around in research and development labs for years, it wasn't until the summer of 1974 that the bar code was unveiled to the public. On June 26, 1974, to be exact, a cashier at an Ohio grocery store scanned a customer's 10-pack of Juicy Fruit gum, and the price magically appeared on the cash register screen. BINGO! The rules had just changed, and we had no idea how much.

In the 30 years since, the ubiquitous black and white striped symbols have infiltrated their way into our daily lives. By some estimates, over 5 billion bar codes are scanned each day. Not counting the occasional yard sale or flea market purchase, try to remember the last time you bought something and a bar code wasn't part of the transaction.

It's been estimated that bar-code technology saves the nation's retail sector something on the order of $30 billion a year in operating costs. Not bad for something that looks more like abstract art than a revolutionary business tool. But beyond that, the codes have forever altered logistics operations. Because they carry so much information that can be captured, reported, analyzed and (we hope) acted upon, bar codes have allowed companies to move their goods through the supply chain at ever-increasing speeds. And therein lies perhaps the bar code's most important contribution to the business world: an exponential increase in velocity in back-room logistics operations.

Still, most of us go about our daily lives unaware of what happens in warehouses and manufacturing plants and distribution centers. To us, bar codes are what allows us to sweep through retail and grocery store checkout lines way faster than we could back in the days of manual cash registers.

I was reminded of that as I stood at the checkout counter one Saturday morning last month at the only full-service grocery store on the outer reaches of Cape Cod. The young woman in front of me was having a monumentally bad day. She'd arrived at the supermarket with what looked to be a five-year-old, a three-yearold and an infant in tow, which meant the deck was already stacked against her. She found herself (as did I) in a sea of shoppers, all elbowing past each other in hopes of getting in and out of the store quickly with the groceries they needed to stock the cupboards at their rented cottages. Alas, as she stood there, with a carriage heaped high with everything from hot dogs to sunscreen to cheddar cheese, the line only inched forward. In fact, it probably didn't seem to her that the checkout line was moving at all.

As I waited patiently for my turn at the counter, it dawned on me that things could be much worse. I imagined the same circumstance 30 years earlier. I imagined how much slower things would be if the heavily pierced and tattooed teenage girl swiping merchandise across the scanner had to pause and find the price tag on every bottle of shampoo and pound of coffee, read the price and then enter each digit into a cash register.

This little daydream brought a smile to my face, but it didn't help the young mother. She knew nothing of that 10-pack of Juicy Fruit gum out in Ohio 361 months earlier. If she had, she probably wouldn't have much cared. And that's a shame. If it weren't for the bar code, she might still be in line.