It looks like they didn’t need a building that large even then, since many windows display the names of other businesses presumably renting out space. There’s Edward Barber Real Estate and Loans, an Equitable Life office, and others.

What style of architecture would this be considered?

[Neo-gothic Flemish Renaissance Revival. -- Dave]

I can't imagine a brewing company need a head office that large these days, especially with the brewery and bottling operation located elsewhere.

I'm confused about the building next door to the Pabst Building. In this photograph and the one posted 1.18.2021 the building next door along the river is the the same building, with company names along the flat roofline and painted between the rows of windows on each floor. But in the photograph posted on 9.24.2015 the building next door has a pointed roof feature, presumably at it's its center, and very different windows in the sloped portion of the Second Empire roof. All the photos are circa 1900 or 1901 and the building next door appears to be the same height in relation to the Pabst building. But, just as the Pabst building is consistent all the way around, does it make sense the building next door would be so different, front and back, when both sides are on public display?

[You're looking at two entirely different structures, on different sides of the Pabst building. - Dave]

Methinks the architect had one too many PBR's.

This must have been the bees' knees -- a swing bridge that maintained electrification for the trolley cars that crossed it. Powered, presumably, by the fermented byproducts of its malty neighbor.