WESTFIELD, N.J. — When an eighth-grade class at Roosevelt Intermediate School tackled Chapter 4 of John Steinbeck’s “Of Mice and Men” one morning last week, the conversation focused on the loneliness of a minor white character known as Curley’s wife.

The next day at the same time, five miles away at the Cedarbrook K-8 Center in Plainfield, another eighth-grade class opened to the same chapter of the same book but paid scant attention to Curley’s wife, spending most of an hour on the sole black character, Crooks.

Similar discussions of the classic 75-year-old novel, about two migrant workers desperately seeking their own land, unfold in thousands of classrooms around the country. But these two sets of students are engaged in an unusual literary experiment, studying the book in a collaboration intended to provide lessons between the lines of Steinbeck’s prose.

In a state stratified to a large extent by race and wealth, the mostly white students in tony Westfield say that they live in a privileged “bubble,” while the Cedarbrook students in Plainfield are nearly all black and Hispanic, and two-thirds of them are poor enough to qualify for free or reduced lunches. On Tuesday, the day after Martin Luther King’s Birthday, 130 of the eighth graders who have been reading Steinbeck side by side, trading questions via Wikispaces, Skype and visits to each others’ schools, will gather for the final chapter in a project that sought to teach them as much about themselves as about Lennie and George.