Here's a hot tip: spend a lot of time on this important document, fill it out carefully, and turn it in early. Why? Because the book marketing team may use much of it to create important aspects of your book, including your media kit and even the copy that will go on your book cover.
Words you write on that page could actually end up on your cover if you do a really good job. They can work as flap copy, as the book's description -- if you have talent for this sort of thing, your own words can even make it into the book's advertising.
"But isn't that my publisher's job?" some authors ask. Hmmm. Let's see. They have how many books on their list each season? And besides, who better than you to perfectly describe your own work? I'm not saying that publishing professionals don't or won't write this stuff, because they do and they will, but I urge authors who are of a mind to do so to try their hand at the art form of the questionnaire.
But when they say 150 words, they mean it!