The editors describe this volume as a basic reference work on science, engineering, mathematics, and medicine. The description seems accurate. The presentations will naturally be more useful to those outside the field than to those inside. Thus the physician would not look here for information about medicine, but perhaps about mathematics, or physics, or engineering.
In general, entries on relatively new subjects, such as computers or space exploration, receive much attention. The section on transplantation of organs is good, and even mentions the first heart transplant, albeit tersely. If you wish to read about lasers in medicine you are directed to "masers" and from there to "medical electronics," for a good brief description.
Other subjects are less well treated. Cryosurgery is disposed of in 30 words (in "Low Temperatures, Applications of"). The section on artificial organs ignores artificial hearts. And I could find no description of the sex chromatin mass