
general public.  'I1,e response to foreign  editions 
of 
this book (in 
French, Italian, Spanish, 
and 
German) indicates 
that 
most readers 
have 
no 
difficulty 
in 
follOwing 
the 
science 
presented 
here, 
and 
can 
appreciate multidisciplinarity. 
To some, 
history (including evolution) is 
~ot 
a science, because 
its results cannot 
be replicated 
and 
thus cannot 
be 
tested by 
the 
experimental method. 
But 
studying 
the 
same 
phenomenon 
from 
many different angles, from many 
diSciplines, each. 
of 
which sup-
plies 
independent 
facts, has 
the 
value oflargely 
independent 
repe-
tition. This makes 
the 
multidisciplinary approach indispensable. 
An important conclusion 
that 
emerges from this work is 
that 
human 
genetic evolution has 
been 
heavily affected 
by 
technolOgical 
innovations 
and 
by 
cultural change, in general. Culture, meaning 
the 
accumulation 
of 
knowledge over generations, is 
the 
main differ-
ence between humans 
and 
other 
animals (the difference is 
one 
of 
degree, because animals, too, learn during 
their 
lives 
and 
transmit 
knowledge 
to 
future generations). Cultural transmission 
"is 
thus an 
important object 
of 
study, 
one 
that has 
been 
dramatically neglected. 
Chapter 
6 
is 
devoted to it. 
'I1,e subject 
of 
this book has significant implications for important 
social problems. 
It 
explains, among other things, why racism is falla-
cious. Genetics is instrumental in shaping us, 
but 
so, too, are 
the 
cul-
tural, social, 
and 
physical environments in which 
we 
live. 
The 
main 
genetic differences are between individuals 
and 
not between popula-
tions, 
or 
so-called "races.» Differences 
of 
genetic origin among 
the 
latter are 
not 
only small (rapidly becoming even smaller with the 
recent acceleration 
of 
transportation, and both migratory and cul-
tural exchange) 
but 
"also 
superficial, attributable mostly 
to 
responses 
to 
the 
different climates in which we live. Moreover, 
there 
are serious 
difficulties  in distingnishing between genetic  and cultural 
differ-
ences, between nature 
and 
nurture. 
My greatest 
hope 
is 
that 
the 
reader 
experiences 
the 
same intel-
lectual pleasure I have with each expected 
and 
unexpected finding, 
uncovering so  many points 
of 
agreement among diSciplines 
that 
have 
been 
kept 
carefully separate for so long. 
VIII