"It is to be regretted that this type of discrimination should exist in any project using federal funds exclusively," he wrote. "With the present unsettled conditions throughout Europe, the United States is itself on trial as the last proving ground for democracy."

Marshall also wrote to everyday African-Americans struggling against racial discrimination, especially in the South.

"Some of the letters ended up on his desk were very illiterate. They were full of misspelling and typos, very difficult to read some of these letters, it's just difficult to figure out what they're saying," says Long. "Marshall would sit at his desk and he would read those letters very carefully and he would craft a beautiful response to them and mail a letter back. In some of the letters that he wrote, we can see a very compassionate, warm, sensitive side of Marshall that we don’t normally see."

Long believes it is important for younger generations to read these letters, and learn about the man whose work still impacts lives.

"I think we can see how he shaped history today, if we look at the White House and we see who is there. I think we can trace the presence of President Obama to Marshall’s work. I think Obama is a very rich legacy of the civil rights work of Thurgood Marshall. Marshall worked for that not only here in the United States, but also worldwide. He assisted some countries in crafting their constitutions, Kenya for example. Marshall played a leading role in helping people think about liberty, freedom and equal justice under law."