AN UPHILL BATTLE

One of the detectives in our story was a police officer. The other was a private investigator. Both women did their work in a world where women and girls are sometimes treated very differently than boys and men.

Humans may be the cleverest animals on the planet, but that doesn't make us perfectly rational or logical. Not even close! Even with our large, powerful, evolved brains, we struggle to make sense of the world, and of each other. Often we struggle to make sense at all. One of the challenges we have often struggled with is that of treating each other fairly and equally. Groups of humans have often felt suspicious toward other groups--perhaps because those "other" people looked different, or lived in another land, or spoke another language, or had different customs. Sometimes, people have even felt that other people were so different that they must be less good, or less capable, or less important.

Judging someone because of a group they're supposed to belong to, and not on their own qualities as a person--"prejudice"--is very unfair. It can also lead to some serious problems. In some places, laws give some people rights that other people don't have (such as the right to vote, or to serve in the military). The social customs of a land may pressure some people to act in one way, and other people in another. Opportunities such as good jobs may be open for some people, but not for others. Rose Mackenberg and Mary Sullivan faced just such obstacles.

SPEAKING WITH THE DEAD?

Mary and Rose worked during the first half of the twentieth century, when American law enforcement was trying to work out how to deal with fortunetellers. People have claimed for thousands of years that they could perform psychic feats such as seeing the future, reading minds, or answering written questions sealed inside envelopes without opening them. In the middle of the 1800s, these ideas took on new life when three American sisters began to perform as "mediums"--supposedly, talented psychics who could see, sense, or speak with the spirits of people who had died. Two of these girls confessed later in life that their performances had been fake, but by that time they had already inspired a new religion, called Spiritualism.

Like most other religions, Spiritualism includes beliefs that are not accepted by mainstream science, such as the belief that the spirits of dead people sometimes communicate with the living. But as far as the law is concerned, it doesn't matter whether science supports a religious belief or not. The Constitution of the United States and the laws of most modern democratic countries protect the right of citizens to hold any religious beliefs they like, so long as they're not hurting anybody. No matter how strange a person's beliefs may seem to those who do not share that religion, the police are not allowed to harrass, arrest, jail, or otherwise punish that person for holding them.

But here's where...