There are enough stories of Romani suffering, past and present, to fill many volumes, but Madeline Potter, the author of “The Roma,” adds a new perspective. Without overlooking or playing down the Roma’s tragic history, she celebrates Romani arts and folklore, honors individual heroes and heroines, and praises the resilience that has ensured the Roma’s survival. Ms. Potter is herself Roma, born in Romania in 1989, and is currently a teaching and research fellow at the University of Edinburgh.