Although Thurgood Marshall and Martin Luther King, Jr., agreed that integration was a central goal of the civil rights movement, they did not see eye-to-eye on methods of achieving it.

Civil rights leaders Thurgood Marshall and Martin Luther King, Jr., were similar in many ways, but they had their differences too.

The first sentence expresses a focused idea that can be developed in a paper. The other sentence is too vague to be an effective thesis.

For more help, see section 53.