Because it can be somewhat confusing, Timothy Zahn's trilogy takes place 5 years after Return of the Jedi. That said, Heir to the Empire is actually the first and only Star Wars book I've ever read. I wasn't sure what to expect since I usually don't care for books from film adaptations, but I was pleasantly drawn into the world. 
 I love how this book shows both sides of the story, flipping back and forth from The Empire and The New Republic. In much of the book, I was actually rooting for The Empire, just because Grand Admiral Thrawn is so suave. The book describes him as a blue skinned humanoid with dark hair, and red eyes that strike fear into the looker. Putting two and two together, he's a Chiss, which is actually pretty cool because you can play a Chiss in the MMORPG, Star Wars: The Old Republic. 
 Another cool character in the book is the Dark Jedi Joruus C'baoth. I was slightly confused at first because I didn't think you were considered a Jedi if you were on the Dark side, but perhaps the word 'Sith' hadn't come out yet, so 'Dark Jedi' is the term this book uses. I really like Joruus C'baoth's personality. He obviously is evil, but he is a very different kind of evil compared to Thrawn. Thrawn's goal is to gain power, but C'baoth has different thoughts in mind. I don't want to spoil them, so you really should read Heir to find out. 
 My absolute favorite character is Mara Jade. I love how her story with Luke plays out in the vornskyr-ridden jungles of Myrkr. It's obvious what she wants, Luke's head, and yet she doesn't end up shooting him at the first opportunity. This whole dilemma of what one wants and what is logically practical fights out in Mara's head, which I feel Zahn crafts so carefully and subtly. Not to mention Mara Jade is so cool and level-headed that it's hard not to love her. What's slightly confusing is that Mara Jade can obviously use minor aspects of the force, but the book makes no reference to whether or not she is a Jedi. One would think this would be a big deal, especially since Luke thinks only he and his sister are the only Jedi left in the Universe. 
 Then there are your standard characters of Han and Princess Leia Organa Solo. They're married, and Leia carries two Jedi twins. Leia is definitely still herself, noble and strong, while keeping Han on his toes. C-3PO and R2-D2 also add light moments in the book. And of course R2-D2 resourcefully saves Luke's life on at least a few occasions in the book. 
 To be honest, I was kind of annoyed at first by the comic aspects of the old team's interactions. It's your typical banter that is prevalent in the films, so at first it felt like rehashed personalities. But once I read further in the book, I quickly adjusted, and even found several of their scenes amusing. The book most definitely has its fair share of "I have a bad feeling about this." 
 Also, to my pleasant surprise, Wedge makes an appearance in the book. Although his role is minor, the geek in me came out and got really excited. 
 There's a lot more in this book, which I haven't even described. There is even a chapter where Princess Leia is on the Wookie home-planet Kashyyyk, which brought a smile to my face, especially when I tried pronouncing the name like how Stephen Colbert does, "Ka-shyy-yy-yy-yy-k!" Also Leia's later interactions with the Noghri are highly interesting, especially after a certain plot twist *wink* *wink*. 
 All in all, I really liked the book, so I give it 4 stars. There are so many great things about Heir, yet it hardly compares to the epicness of films Episodes IV-VI; however, any Star Wars fan would be greatly pleased by this book. Although, when you start to think about how difficult it is to please die-hard Star Wars fans, I might take that back, but for any level-headed Star Wars fan, this book is bound to please.