English-to-Spanish book translation is a service that some specialist translation companies offer. Books and other literary works vary significantly in their size in terms of word count (the standard measure for translators to determine a project’s scope). It’s not unusual for a book’s word count to range up to several hundred thousand words.
Translation companies are considered to be a good resource for literary work authors seeking translation into Spanish, or other languages. Since translation companies maintain active relationships with many translators, each with unique backgrounds and translation project experiences, companies have the ability to assign the best suited translator to a project.
Quality control is an important part of the process in translation of books just as in translation of other texts. Typically a second translator will review the translation work of the primary translator. This proofreading phase (sometimes called revision phase) is considered essential to ensure a high quality translation ready for publication.
Standard practice is for book translators to be native speakers in the target language. Keep in mind that translation is a specific skill that not all bilingual speakers can perform at a professional level. Also be aware that interpreters (linguists that work with spoken language) are not always translators (linguists that work with written language), and vice versa.