Dennis Ritchie is best  known  as  the  creator  of  the  C
programming  language  and  (along with Brian Kernighan) as
co-author of the book "The C Programming Language." Ritchie
worked together with Ken Thompson,  who  is  credited  with
writing   the  original  version  of  Unix;  they  were  so
influential on Research Unix that Doug McIlroy later  wrote
"The names of Ritchie and Thompson may safely be assumed to
be attached to almost everything not otherwise attributed."