Break out the fireworks and print the T-shirts: Pittsburgh does indeed have more bridges than any other city in the world.

In his new book, "The Bridges of Pittsburgh," Bob Regan presents a carefully reasoned analysis that gives the city bragging rights over that wanna-be slackerville, Venice, Italy. After laying out his research and ciphering, Regan gives us the final count within city limits: The "best estimate" for Pittsburgh is 446, while Venice has "approximately 400 [small] bridges." Another "City of Bridges" title contender, St. Petersburg, Russia, is also quashed, weighing in with a mere 304 bridges.

But Regan's book isn't only about kicking bridge butt on an international scale. "The Bridges of Pittsburgh" is a user-friendly guide that offers up bridge history and a bridge glossary along with bridge pioneers, aesthetics, engineering, safety, novelties and more. Measuring 6 inches by 9 inches, it's small enough to keep in a handbag, the glove compartment of a car or the saddlebag of a bike, and for good reason: A portion of the book is devoted to walking, biking, driving and boating tours of bridges.

That's part of what differentiates it from other books on Pittsburgh bridges, the most recent spate of which began in 1999, when Pittsburgh History & Landmarks Foundation published Walter Kidney's "Pittsburgh Bridges: Architecture and Engineering," a beautifully designed and illustrated history that sells for $49.95. Two years later, Carnegie Library of Pittsburgh published Robert J. Gangewere's "The Bridges of Pittsburgh and Allegheny County," a $5, large-format paperback heavy on innovation and technology and still available at the Oakland library and at the Engineers' Society of Western Pennsylvania, which sponsored it.

Add to that the most complete and authoritative source of all -- graphic designer and computer systems manager Bruce S. Cridlebaugh's Web site, www.pghbridges.com -- and it's clear we are living in an unprecedented new age of widely disseminated information about and appreciation for Pittsburgh bridges.

Regan sees his book, priced at $22.95, as a complement to those efforts, and one that is a more personal exploration, written by the same man and illustrated in black and white by the same photographer, Tim Fabian, who two years ago gave us "The Steps of Pittsburgh," from the same publisher, The Local History Company of Shadyside.

A visiting research professor at the University of Pittsburgh and a software mapping consultant, Regan is a dedicated cyclist who logs about 2,500 miles a year, along the way experiencing many of the city's bridges in a more intimate way than most of us can imagine. As a mapmaker, Regan is naturally keen on showing us just why Pittsburgh has so many bridges: Topography is destiny, as a relief map illustrates.

He also maps all of his tours, including one featuring the breathtaking, ravine-spanning Wilksboro Avenue footbridge in Brighton Heights, which, on the warm, damp afternoon I first experienced it a few years back, was like walking through the rainforest treetops.

For bridge aficionados, reading "The Bridges of Pittsburgh" sometimes will feel more like Google grazing than nutritious feeding. A few times I was eager to learn more about a subject, only to find Regan had moved on to something else, as in the too-short chapter on bridges and theoretical mathematics.

The perfunctory layout could be more adventurous and the editing needs a stronger hand and sharper eye. The book leaves us in mid-sentence on page 83, for example, wondering where the railings from the demolished Brady Street Bridge ended up. At the Station Square "T" station, Cridlebaugh reports.

And chapter headings labeled "The Big 'uns" and "Historic Big 'uns" made me cringe. Is Al Bundy's -- and for that matter, the culture's -- moronic fixation with big American breasts an image we really want to associate with big bridges, the pride of Pittsburgh, even in jest?

The book will be released June 12 to coincide with the opening of the Engineers' Society's International Bridge Conference, held annually here for 23 years.

And while we're on the subject, why doesn't Pittsburgh better celebrate and nationally promote its bridges? If Washington and Greene counties can have a Covered Bridge Festival, why doesn't Pittsburgh have an annual City of Bridges festival, during which we close to traffic a different bridge for a day or two each year and open it up for food and fun during the bridge conference?

With Regan offering proof that Pittsburgh is unequivocally the City of Bridges, it's time.