Doctor Grasser hardly needs an introduction to the leather trade of this
country in its scientific aspect, but if one be sought for, none could
serve the purpose better than a translation of the book herewith
presented to the British-speaking public.

Viewed with curiosity from their start, the synthetic tannins
needed--like many other important discoveries--an extreme emergency for
the purpose of showing their value. The Great War provided the
opportunity of which chemical industry was to avail itself, and to-day
we do not only see synthetic tannins placed upon the market as a
veritable triumph of chemical technology and a creditable triumph of
manufacturing chemistry; we also see their immensely practical qualities
established as a fact, and, as the author aptly remarks, no modern
tanner can to-day dissociate himself from the use of synthetic tannins
for the production of leather in the true sense of this word. There is
no branch of leather-making where synthetic tannins cannot help and
improve processes already established.

The immense number of substances patented by German manufacturing
chemists for the purpose of producing synthetic tanning materials is
almost staggering. In view of this fact it is doubly pleasing to see
that British chemists have found new ways, and are able to produce
equally good and more varied synthetic tannins than has hitherto been
deemed possible. The originator of these products and his acolytes
must at least share the credit with those who, in spite of the
limitations necessarily set by the former, have been able to find new
and better ways.

In his book Dr. Grasser gives a short review of the necessary forerunner
of any work upon synthetic tannins: the investigations and syntheses of