There are many synonyms for the phrase "write one book," depending on the context and purpose of the writing. Some of the most commonly used synonyms include "author a single tome," "pen a solitary manuscript," "compose a self-contained volume," or "draft an individual publication." Other options may include terms such as "create a singular text," "construct a standalone work," "produce a lone opus," or "craft a solitary piece of literature." The choice of synonym will depend on the writer's goals and the intended audience or market for the book. Regardless of the term used, the act of writing a book requires dedication, skill, and perseverance.