Systematically biased editing, persistently maintained, can occur on Wikipedia while nominally following guidelines. Techniques for biasing an entry include deleting positive material, adding negative material, using a one-sided selection of sources, and exaggerating the significance of particular topics. To maintain bias in an entry in the face of resistance, key techniques are reverting edits, selectively invoking Wikipedia rules, and overruling resistant editors. Options for dealing with sustained biased editing include making complaints, mobilizing counterediting, and exposing the bias. To illustrate these techniques and responses, the rewriting of my own Wikipedia entry serves as a case study. It is worthwhile becoming aware of persistent bias and developing ways to counter it in order for Wikipedia to move closer to its goal of providing accurate and balanced information.