The thematic, psychological, and cultural concerns of a writer are more relevant than whatever literary mode he or she chooses to deal with in any given novel.
I'm 82 years old, wherever I go everybody knows me, but here's why... I'm a merchandiser, I'm not just a writer, I stay in every avenue you can think of.
If you're a singer you lose your voice. A baseball player loses his arm. A writer gets more knowledge, and if he's good, the older he gets, the better he writes.
Above all, a query letter is a sales pitch and it is the single most important page an unpublished writer will ever write. It's the first impression and will either open the door or close it. It's that important, so don't mess it up. Mine took 17 drafts and two weeks to write.
