Imagine a Minneapolis so small that, on calm days, the roar of St. Anthony Falls could be heard in town, a time when passenger pigeons roosted in neighborhood oak trees. Now picture a dapper professor conducting his ornithology class (the university's first) by streetcar to Lake Harriet for a morning of bird-watching. The students were mostly young women--in sunhats, sailor tops, and long skirts, with binoculars strung around their necks. The...