The importance of being clear on the purpose of your book cannot be overstressed.
If you are vague from the outset, you will struggle later on to connect your book with its intended audience.
A simple, one-line statement that reads like a mission statement may be helpful.
A mission statement has three important elements: what the book purports to be or do for the reader; who the audience is, specifically; and, what outcome the reader should achieve from reading the book.
For example, this book captures the imaginations of children between the age of 4 and 9 years old, as they follow the main character on an adventure and learn to solve and develop interpersonal communication skills.
Alternatively, this book highlights the learning styles of young adults and presents a creative method for bridging left and right brain thinkers to improve academic performance.
If you are clear on a statement along these lines, your writing will be appropriately oriented to your audience, and all of your marketing and promotional efforts will focus correctly on your intended buyers.
Being vague only ends up confusing people or causing them to believe the book is not relevant to their specific interests.
To illustrate the need for clarity, consider three different authors who describe their books generally as "children's books".
On closer inspection, we find that the first author writes a series of children's stories, each highlighting the adventures of the same main character.
Each adventure is short and richly enhanced with artwork and pictures.
The children may learn behavior or communication skills through these stories, but they are primarily entertainment.
The second author has a collection of books designed to address several child development topics using a creative, story-telling approach.
The writer has a PhD in Psychology and years of experience working with children.
Each book tells a story, but the stories are lengthy and somewhat complex.
In fact, these books are intended as a developmental aid primarily for parents or other caregivers to read and discuss the story and the topic in question with the child.
The third author's books are the result of years of working with children on learning and other developmental disorders, such as dyslexia, ADHD, and other issues that prevent children from advancing or progressing at the same pace as their peers.
These books include stories and games that are effective tools for counselors, therapists, and parents to help children learn to overcome their specific challenges.
Although all three of these authors describe their works as "children's books", we can plainly see there is a vast difference between them and a little clarity in describing each will more clearly articulate the purpose and the intended audience for each.
The result is that they are more likely to reach the buyer they want to reach, and for the reason that buyer wants to buy.