August Books 7) Heir to the Empire, by Timothy Zahn
This was recommended to me by matgb and rmc28, and they made a good call. Set five years after Return of the Jedi, Luke, Leia and Han Solo are intimately engaged in consolidating the New Republic, and get enmeshed in an attempt by an imperial admiral to bring it all down. There is a very real sense that this book builds on and respects the cinematographic canon, but also dares to add a few more elements - in particular, a new more military female protagonist who helps balance Luke and Han. A very satisfying read.