"Cross Currents" was originally written in 1990, some five years after Becker's groundbreaking "The Body Electric", and is partly an up-date to the earlier book and partly a stronger warning against the possible effects of electropollution.
However, by the time of writing "Cross Currents", the author had retired from academic research [or, as some would see it, been forced into premature retirement by those parts of the scientific/industrial establishment that were rather frightened by the implications of his work being made public...] so there's not much radically 'new' here beyond "The Body Electric".
For anyone reading this book today, it's biggest drawback is simply that so much has happened since the 1980's and early 90's: think of the billion-or so mobile phones now in use around the planet and the resulting additional EMF; Becker was very concerned by the man-made electro-magnetic environment twenty-odd years ago, who's around to continue his work today?