After finding my granparents old stereoscope viewer and viewer cards, I became quite fascinated. They are wonderful 3D views of Victorian life, travel, etc.(1800's) I went online to 2 great web sites re: stereoscopes. One recommended this book as the best. And indeed it is. Has in depth info. on all aspects of stereoscopes and the later development(40's- 50's) View Master. I have been very delighted with my stereoscope, (less with my viewmaster), and with this book. Much history, humor, and pleasure from the viewer cards, and much knowledge about them from this book. Very pleased that I bought it.