As of my last knowledge update in January 2022, I can't provide specific details about the top book writing company in the USA, as rankings and reputations can change over time. However, I can give you a list of well-known and reputable book writing and publishing companies in the USA. Keep in mind that it's essential to research and consider your specific needs when choosing a company. Here are some notable ones:

Reedsy:

Reedsy is an online platform that connects authors with professional book editors, ghostwriters, and other publishing experts. They have a wide network of experienced professionals.

Lulu:

Lulu offers self-publishing services, including Top Book Writing Company in USA, editing, formatting, and distribution. They assist authors throughout the self-publishing process.

Xulon Press:

Xulon Press specializes in Christian self-publishing and offers a range of services to help authors write and publish their books.

Archway Publishing (a Simon Schuster company):

Archway Publishing provides a range of self-publishing services and is backed by the renowned publishing company Simon Schuster.

BookBaby:

BookBaby is a self-publishing company that offers a variety of services, including editing, design, and eBook and print book distribution.

Balboa Press:

Balboa Press is a self-publishing division of Hay House, a well-known publisher in the self-help and spiritual genres.

Dog Ear Publishing:

Dog Ear Publishing offers a range of book publishing services, including writing, editing, design, and distribution.

iUniverse: iUniverse is a self-publishing company that provides authors with a suite of publishing services, including writing, editing, and marketing.

Greenleaf Book Group:

Greenleaf Book Group offers publishing and distribution services for authors, including ghostwriting, editing, and marketing.

Mascot Books:

Mascot Books is known for helping authors self-publish children's books, young adult novels, and non-fiction works.

When choosing a book writing or publishing company, it's important to consider your specific needs, budget, and goals for your book. Research each company's offerings, read reviews, and reach out to them for more information to find the best fit for your project. Also, be aware that new companies may have emerged since my last update, so it's a good idea to explore the latest options in the publishing industry.