When I was 19 years old, I went to Wall Street. It was narrow, dark, secretive—worthy of the cash that I imagined rested behind those vault-like façades. It was my first encounter with shadows bestowing a sense of place, in this case a sense of importance. Shadows affect people in other ways. They hint of secrets. They evoke menace, as in film noir or in “The Shadow.” Caravaggio used them to bring drama to his paintings. In Boston, shadows are the bogeyman used to whip real estate developers into shape, causing them to lower the height of their buildings. But shadows are complicated. If we like them, we call them shade. The Friends of the Public Garden persuaded state legislators to pass a law in 1990 restricting new shadows on the Boston Common and Public Garden. This year New Yorkers urged their lawmakers to pass similar legislation protecting Central Park from such effects. Shadows on parkland can limit the kinds of vegetation that will survive, and they can also detract from users’ enjoyment of a park in which people seek sunlight as well as shade. That all seems reasonable. But even the relationship between shadows and gardens is complex. Roses need only six hours of sun daily. Many other flowers and trees, not that much. Shade gardens are easier to maintain—less weeding needed. And consider my city garden. This 40-by-16-foot plot gets a one-hour sliver of sun that steals slowly around the garden walls, mostly in June. Yet everyone who visits it pronounces it beautiful. (I agree.) So much for the benefits of sunlight. Another prime shadow location is on the southern side of Boston’s east-west sidewalks. The sidewalk across from my building has not seen sunlight since at least the 1890s. Five-story tenements cast it in total shadow. No one notices, and certainly no one has complained. Massachusetts has passed other shadow legislation—Chapter 91, for example, addresses shadows. But Boston didn’t invent antipathy to shadows, and this city didn’t pass the first legislation about them. In 1901 New York City limited height in residential areas in the Tenement House Act, partly to reduce future shadows. In 1915, New York passed zoning that spelled out how commercial buildings would step back, narrowing as they rose higher, so they would cast less shadow. This zoning felicitously determined the graceful shapes of the Empire State and the Chrysler Building. Later zoning was not so kind to the eye or the pedestrian. By 1961, architects were smitten with the International Style, and New York changed its zoning again. This time, instead of old-fashioned step-backs, the city used “floor-area ratios” to control height and shadows, but provided height bonuses to skyscrapers that gave the public “open space.” The plazas around such buildings did reduce some shadows, but they also increased wind, destroyed street life and presented a barrier to entering a building. Boston officials have been trying for years to eliminate such plazas and bring buildings back to the sidewalk. Not all skyscrapers are known for shadows. My favorite is London’s “Walkie-Talkie,” a bulky, top-heavy, 525-foot leaning glass tower, the reflection of which was so strong that it melted a Jaguar on a nearby street. Some now call it the “Fryscraper.” Be careful what you wish for. I have my own sunlight-creator. A large, newish, glass-clad building behind my house reflects sunlight every April and October for a few days, bringing sun into a couple of my north windows. It creeps me out. Rather than tweaking design, New York style, Boston has typically, after contentious neighborhood processes, asked developers to take off several top floors. HYM Investments agreed to lower its 600-foot Government Center building by 75 feet. Did this benefit anyone? Measuring shadows involves many subtleties, but reducing the height of a 600-foot building by 100 feet would typically mean its shadows would be reduced by one-sixth, according to Matt Littell, architect and principal with Utile Design and a consultant to the Public Realm and Watersheet Activation Plan and Municipal Harbor Plan for the Downtown Boston Waterfront. One-sixth isn’t much in a city where most shadows land on the rooftops of surrounding buildings. Moreover, this project will bring new sunlight to Congress Street, which we’ll probably complain about when we’re walking along on a hot summer day. Other new projects are coming up, and they’ll all cast shadows, even if they are only three stories. The 600-foot TD Garden tower along Causeway Street will cast the most shadow over the TD Garden and North Station. Some will even increase sunlight in certain places. The Harbor Garage developers say their proposed buildings, one of which is 600 feet tall, would cast only fleeting shadows off-site and actually bring more sunlight on the ground at the site itself, compared to the current condition. Should more sunlight mean a developer can build higher? It’s not that we shouldn’t consider shadows. But we should realize their presence is more nuanced than they have been made out to be. And if we insist that a building get shortened by 100 feet, or changed in some other way that affects shadows, it should actually matter.