I am writing a book and I need to set the odd/even margin on the binding side.
\usepackage[top=2cm, bottom=2cm, left=1cm, right=1cm, headsep=14pt]{geometry}
I need left = 2.1cm for odd pages and for even one left = 1.0cm.
I found
\oddsidemargin
\evensidemargin
but those change all four sides.
How can I set two different margins on odd/even pages?

bindingoffsetfor the packagegeometry. – Jana Feb 19 '13 at 10:16