Information from observations made at fire scenes covers the approach to the scene, the arrival at the scene, and the examination of the condition and contents of the building. Indicators of arson are explained in detail. The use of the arson investigator at the trial is explained, and a checklist of items that might be considered in determining the qualifications of expert witnesses is provided. Guidelines on cross-examination of witnesses emphasize the need to focus on poor observation by the witness. Methods of handling well-prepared witnesses are explained. Differences between handling the arson expert and other expert witnesses are explained. Questions concerning experiments conducted by such experts and situations where the defense admits the incendiary origin of the fire but denies that the defendant set it are also discussed.