There are several places where I compress time for the sake of keeping the story moving, dealing with both the facts recorded in Herodotus and in the Bible. Most of these would go totally unnoticed, but the historian in me demands I alert you. 
The first time comes when the army is en route to Greece. After they cross the Hellospont, there’s a peasant man who shouts to Xerxes, “Mighty Zeus, why do you parade about under the guise of a Persian and call yourself Xerxes? If you wish to destroy Greece, you had no need to bring all of mankind with you–you could have done it under your own power.”
This was just too hilarious for me to leave out. =) But it didn’t really need a whole scene to itself, so I combined it with a meeting that Herodotus records as happening a few weeks later. Namely, when Xerxes calls Demaratus, the exiled king of Sparta, to ride with him and questions him on whether or not any Greeks will resist him.
Now, when it comes to conversations recorded by historians, I took a few liberties. I stuck with the gist of them, but in order to avoid infringing on copyrighted translations—and to shorten them into manageable chunks—I reworded everything. This goes not only for conversations like the one Xerxes had with Demaratus, but also with the ones that come from Esther.
Which brings me to the condensing of time that you’re more likely to notice. In the main events of Esther, there are several things that happen in a back-and-forth way when she’s sending messages to Mordecai. In actuality it was quite a series of message sent, message received, reply sent, reply received, but, well, I didn’t have time for that. =) I condensed it all into one exchange.
Also, I push into a week what really took over a month—that time between when Haman issued his proclamation and when Esther went before the king to ask him to change it. I wanted to stick to the timeline in the Bible, but it would have involved just skipping that month entirely, since nothing happens during it. For the sake of simplicity, I compressed—and provide you with this note on it. =)