Although various methods for the evaluation of intelligent systems have been proposed in the past, almost no techniques are present that support the manual inspection of knowledge bases by the domain specialist. In this paper, we discuss a collection of appropriate visualization techniques that help developers of a knowledge base to interactively browse and analyze the knowledge base in order to find deficiencies and semantic errors in the implementation. We describe standard visualization methods adapted for knowledge base analysis, and we propose a novel visualization technique to support the manual inspection task. The application of the shown methods was motivated by daily practice of knowledge base development.