Baker's fiction generally de-emphasizes narrative in favor of careful description and characterization. Baker's enthusiasts appreciate exploration of the human psyche.
Baker has been a fervent critic of what he perceives as libraries' unnecessary destruction of paper-based media. He wrote several vehement articles in The New Yorker critical of the San Francisco Public Library for sending thousands of books to a landfill, the elimination of card catalogs, and the destruction of old books and newspapers in favor of microfilm. In 1997, Baker received the San Francisco–based James Madison Freedom of Information Award in recognition of these efforts.
In 1999, Baker established a non-profit corporation, the American Newspaper Repository, to rescue old newspapers from destruction by libraries. In 2001 he published Double Fold, in which he accuses certain librarians of lying about the decay of materials and being obsessed with technological fads, at the expense of both the public and historical preservation.
Baker describes himself as having "always had pacifist leanings."