Because they were an informal group, and because a principal group activity for many was rhythm and movement, they did not look like a classical resistance organisation. This helped them elude the Gestapo. But it also meant they did not get the recognition that was their due after the war. I am continuing to research into the Bund. You met many interesting people whilst researching the book, many of whom had conflicting stories.
Historians have no magic ingredient for getting at the truth.
Sometimes, one concluded that the differences represented alternative ways of seeing and that it would be wrong to try and reconcile them, or to label one as false. But sometimes, where two or more different kinds of record independently corroborated each other, and challenged elements of other testimonies, it became clear that errors of fact were contained in some of the testimony. I did not assume, as a matter of principle, that memory was flawed and the written record always true. But it is obvious that written records are by and large not amended by time, or the evolution of the subject, in the way that memory can be. No historian has a 'science' of memory.