More and more these days I am hearing from people that they enjoy writing and are curious about the world of professional writing. It just so happens that I have some experience and access to resources in this area. The book I am now recommending to writers (who are often avid readers) is called Starve Better: Surviving the Endless Horror of the Writing Life, by Nick Mamatas. Nick is not only a Bay Area local, he is also a friend of mine. If you look Nick up on the Internet you will discover that he has solid credential and is a prolific writer. People I have recommended this book to have found it both entertaining and informative, and very readable.
On a clinical note, I meet a number of adolescents and young adults who have professional aspirations, but are generally unwilling to do anything (like read a book) to advance their knowledge of the desired career. As a parent I would recommend you listen for and take seriously these aspirations, and then insist that your child pursue them (beyond simply talking about them). Reading books about your desired career is one option. Attending summer camps, looking for internships are other ideas. Regardless the desired profession, encouraging your child to get a part time job is about the best training you can give them for the work world at this point in their life. Internships and summer camps might teach specific skills, but part time jobs train adolescents in "soft skills", or those skills that are valued in nearly every profession, such as being on time, being conscientious in your work, and speaking respectfully to one's boss.
As a final note, reading books is not sufficient preparation for becoming a writer any more than playing video games is sufficient "research" for a career in the video game industry. Encourage your children to "do" and "create". If they want to become a writer, have them actually write or attend writing workshops. Nick has his own (not so positive) opinion of writing workshops, but it should be noted that Nick also runs such workshops.