Edward Paul Brennan was a nobody. One of us.

Born in 1866, he made deliveries for his father's grocery store, then worked downtown at the Lyon & Healy Co. music store as a bill collector and later as building superintendent.

Yet few individuals in Chicago's history have had as much impact — for the good — on the daily lives of Chicagoans, suburbanites and visitors to the city.

That's why, on Friday, a little before noon, a small ceremony will be held to officially unveil the honorary street designation of the corner of State and Madison as Edward Brennan Way. On hand will be Ald. Brendan Reilly, 42nd, who sponsored the designation ordinance, and Brennan's daughter, Adelaide, who will turn 99 that day.

No intersection is more central to the identity of Chicago as State and Madison, and it's an apt location to honor Brennan since he's the one who gave the corner its prominence.

In the summer of 1901 when he turned 35, Brennan took an armload of maps with him on vacation to Paw Paw, Mich., and came back, like a prophet from the desert, with a detailed plan for helping people find their way in what was then a very chaotic Chicago.

How chaotic?

Well, because of wildfire annexations of neighboring villages and towns in the 1890s, Chicago had boomed in land, population — and confusion.

There were three different systems for numbering homes and businesses — one for the North Side (north of the main branch of the Chicago River and east of the river's north branch), one for the South Side (south of the main branch and east of the south branch) and one for the West Side (west of the north and south branches).

Then there was the duplication of street names. Chicago, in 1901, had nine Sheridan streets, nine Forest streets, 10 Oak streets, 13 Washington streets, 13 Center streets and 14 Park streets.

And, to further muddy the waters, there were what Brennan called "broken link" streets. These were streets that, because of Chicago's grid, went from one end of the city to the other, but were interrupted at various points. Such a street, often, would have one name on one side of the interruption and another on the other side.

For instance, depending on where you were in the city, the street just west of Halsted was called Lime Street, Reta Avenue, Craft Street, Newberry Avenue, Florence Avenue, Dayton Street or Green Street.

So Brennan — no expert, just a do-gooder — drafted his plan, summarized it in a letter to the Chicago Record-Herald and then, with the help of his second cousin, Charles Byrne, a reform alderman, submitted his detailed proposal to the City Council.

That plan called for:

•Rationalizing the numbering system by centering all addresses on State and Madison.

•Giving 1,000 numbers for each mile. (Before adoption by the council, this was changed to 800 numbers per mile. Thus, Pulaski Road at 4000 west is 1 mile east of Cicero Avenue at 4800 west.)

•Giving odd numbers to the east side of north-south streets and to the south side of east-west streets. And even numbers to the opposite sides of the street.

•Abolishing all duplicate names.

•Giving broken-link streets a single name.

•Using street names beginning with the same letter to designate north-south streets within the same mile as an indication of how far west they are of State Street. (That's why, for instance, most of the streets between Pulaski and Cicero begin with a "K." And then there are the "L" streets, and then the "M" streets, and so on.)

After years of debate, the council approved Brennan's numbering system in 1908, and it went into effect in 1909, everywhere except in the Loop. It worked so well, though, that, five years later, the Loop addresses were reoriented to State and Madison.

For nearly four decades, Brennan, a soft-spoken man who wore rimless glasses, worked tirelessly to get the rest of his plan in place.

At his urging, the council gave new names to hundreds of streets, of which at least 130 were suggested by Brennan. (He didn't always win. Some broken-link streets, for instance, still have multiple names today.)

As he went along, Brennan got the backing of the City Club of Chicago and large businesses, such as Marshall Field, but it was his stick-to-it-iveness that won the day. One city official estimated that, in lobbying for his proposals, Brennan attended 600 City Hall meetings.

The honorary designation of State and Madison as Edward Brennan Way is the most prominent tip of the council's hat to Brennan's legacy. But not the only one.

In 1947, five years after his death, the council named a two-block street in a new subdivision Brennan Avenue.

It's easy to find. It's between 96th and 98th streets at 2300 east.

Patrick T. Reardon, a former scholar-in-residence at the Newberry Library, is researching two books about Chicago. He will speak at the dedication ceremony Friday.