Thirty years later, after a career as a magazine photographer specializing in images seen through a microscope, Vishniac showed the pictures in the first comprehensive exhibition of his work. Now his ghetto photographs of children, rabbis and street peddlers have finally been published. To Give Them Light (160 pages. Simon & Schuster. $45) is a testament to the cruel calm before the Holocaust. Looking at this vanished community, we can shudder and curse history. But we can also see ourselves in those who were persecuted and realize the blow to our own humanity.