I picked up To the Golden Shore: The Life of Adoniram Judson in June and devoured it over the course of a week. Judson was a 19th century American missionary to Burma and his story is amazing and heartbreaking at the same time.
Courtney Anderson's biography of Judson doesn't shy away from describing the emotional and spiritual toll Judson paid to bring the gospel to Burma. I appreciated the honesty. If you're wondering what biography you ought to read next you'd do well to pick up this one.