Pick of the paperbacks; The Mill Girls, by George Larkin.New York: Tower Books. $2.50.

Larkin provides a well-researched look at the New England industrial era of the mid-1800s in this novel set during the early days of Lowell's textile industry. It was an era that began in a burst of idealism, only to slide into the same problems that bedeviled other mid-19th-century factory communities as profit motives became paramount. In addition, Larkin gives us a useful look at how far the United States -- for all its present imperfections -- has come since the Lowell of "The Mills Girls."

Emily, the central character, in a sense symbolizes all Americans who have ever sought and fought to improve social conditions in their nation. She herself is a young farm woman who, like many of era, went to work in the mills to earn money and, in the case of the early Lowell mills, to gain an education.

In the process a shy young woman becomes a staunch though always appealing leader, standing for what is right, as she seeks to prevent her mill colleagues from being taken advantage of. It doesn't come easily --time frame of the book. But, as we learn from the author, such protests against inhuman working conditions planted the seeds of unionism that ultimately led to an end of the exploitation of the Emilies of this world.

Although the book seems a little slow getting started, the pace picks up. Altogether, it is a good first novel.