Rosalind Franklin contributed the XRay Crystallographic data that was critical to the determination of the physical and chemical determination of the structure of DNA in 1952 by Jim Watson and Francis Crick. She died in 1958 without knowing the extent that her contribution really made.
The author states that the purpose for writing the book was to set the record straight on who Rosalind Franklin was in contrast to the portrait painted of her by Jim Watson in Double Helix: A Personal Account of the Discovery of the Structure of DNA. Sayer's book was written in 1975, just 7 years after the publication of Warson's book. Sayer was also a person friend of Franklin's.
One reviewer of the book stated that anyone who has read Watson's Double Helix "owes it to Rosalind to read her story, too." Well, I think the converse is equally true. I read Double Helix too this month just for contrast. If you can get past Watson's cutting commentary about virtually everyone he encounters, you will get a sense of the brilliance of the chemical argument leading to the discovery of DNA's structure. Sayer's book clearly shows that Franklin had the correct structure in her notebooks as early as 1951 (and was not the "antihelical" wet blanket described by Watson), but meticulous chemistry was also required to get the final, self-replicating molecular structure. Sayer did not go in to detail about that aspect of the work.
Had Franklin lived to 1962, it would have been hard for the Nobel Committee to overlook her contribution.