The Double Helix is written by James Dewey Watson.  The book starts off with Watson working in Copenhagen on his post-doctorate research with supervision by Salvador Luria.  He worked there for about one year before he worked at several other places.  Watson became increasingly interested in DNA and genes starting with college.  He also became increasingly more interested in crystallography.  Watson, who decided to start investigating DNA, started his research at Cavendish Laboratories at Cambridge University.  At Cambridge he meets his future "right arm," Francis Crick.  At Cambridge, they used X-ray diffraction methods or crystallography to study the protein structures.  The crystallography method was partly discovered by a man named Sir Lawrence Bragg.  This is where Watson learns to use the X-ray diffraction method.  He decided to work on Tobacco Mosaic Viruses (TMV).  This did not help...