Book designers
United States
The United States has the largest concentration of professional book designers, serving everything from indie novels and children's books to complex nonfiction and cookbooks. Many US book designers work across both print and ebook formats, and a good number offer full-service packages that include cover design alongside interior layout.
Site list
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Conclusion
Ask to see a designer's portfolio in your specific genre or format, since the conventions for a novel's interior look very different from those of a cookbook or an illustrated children's book.