The Catalan is normally considered a separate line from the QGD. You will need a different book for it. Which QGD are you playing? Right now the slav is generally regarded as giving black better chances than the QGD.
QGD repertoire books?

"Winning with the Catalan" by Angus Dunnington.
"Play the Catalan" by Davies is supposed to come out this month!
The Catalan is normally considered a separate line from the QGD. You will need a different book for it. Which QGD are you playing? Right now the slav is generally regarded as giving black better chances than the QGD.
I play the Tartakower , sometimes I throw in a Tarrasch or Cambridge Springs.
Anybody know of any good QGD repertoire book that covers the Catalan? I can't believe I haven't found one that does. Should I switch to the Slav?