In our experience, all books about dc are not worth buying. Synopsys documentation is very good and much better than any book you could buy. But the best thing for start is synopsys chip synthesis workshop, which is in the form of slides. And maybe you could combine it with the chip synthesis lab guide. DC reference manual covers same things as user guide, but 3 times bigger. Advanced chip synthesis workshop is the next step, when you have enough experience.
(the suggestions from the edaboard)
But in my opinion, the synthesis concepts and practice are very importmant! We could search some documentation from the web! And the advanced chip synthesize is reconmmandation! And you could contact me through the e-mail : [email protected] for some docs. In order master the use of the synthesis tools, the best way is to do some experiment!