Rachel Kats is the daughter of Meir Shmuel Kats and Margareta Ruth Mosler Kats. She was born on August 17, 1935 in Almelo, a small town in the Netherlands near the German border. Her father worked as a physician and her mother as a nurse. Her older brother Bernhard was born in 1933. In May 1940, Germany invaded Holland. As the situation of Dutch Jews became more perilous, the family went into hiding in the summer of 1942. The family was able to stay together at first, but later had to split up as it became too difficult to hide four people in one locale. From August 1943 until the end of the war, Rachel was hidden in the Nyverdal area: first in Hulzen, then in Nyverdal and finally in Marle. She was hidden through the efforts of Protestant schoolmasters and their families, all of whom were active in the underground. In Hulzen she was aided by the family of Hielke ten Brug, in Nyverdal by the Ponsteen family, and in Marle by the Mulder family. Rachel was liberated in Marle by the Canadian army at the age of 10. Though all of her immediate family survived, most of her extended family perished including her maternal grandfather who died in a Dutch concentration camp, and her maternal grandmother who perished in Sobibor.