Hi Jenna

It's true that many designer's get into book design after working in other areas of design for a while, but there's no prescribed path as such. Publishing houses tend to have one or two art directors and a relatively small team of in-house designers but the bulk of design work is usually put out to freelancers. It's a bit of a myth that art directors in publishing will only give work to freelancers who have previous book design experience. If you have work in your portfolio that reflects your abilities to handle large volumes of images and text (but not a book as such) that will help, but a good art director will see any potentential regardless of the types of project. In the first instance, if you're keen to work in book design try contacting a rage of illustrated book publishers with examples of your work.

If you do secure a project from an illustrated book publisher it's likely that it'll be a presentation (referred to as a blad in the industry) to begin with. Practically all illustrated books begin their lives in this way, particularly if they're being published as a co-edition with a US plus a UK/Australian/Translated edition. It's a good way for art directors to test the water with designers new to book publishing as it's only a commitment to a few spreads and cover concepts, rather than a complete book. If the presentation goes well it's normal (and considered polite practice) for the designer to be offered the complete book layout.

As Scott mentioned above, it's hard and challenging work and the level of remuneration isn't as high as other areas of design, but it's incredibly rewarding. Good luck with it.

Tony