During cross-examination of a prosecution witness, is the defense allowed to to introduce topics not covered during direct examination?

The party calling the witness to the stand conducts a direct examination of that witness. Opposing counsel will then have a chance to cross-examine the witness. A basic rule of direct examination is that the attorney cannot ask leading questions. Leading questions are those that suggest the answer to the question. For example, on direct, the question, "Isn't it true you were driving a red car that night?" is a leading question. The question on direct should be asked, What color was the car you were driving that night?" Asked that way, it doesn't suggest the answer. When your lawyer gets up to cross-examine that same witness, he or she is allowed to ask leading questions. Another general rule is that during the cross-examination, the questions must relate to the subject matter asked on direct examination. (Questions pertaining to witness credibility and impeachment of the witness are also allowed.) As for bringing up and asking questions about an unrelated topic during cross-examination, while the general rule is no, you can ask permission from the judge and explain why you need to do it, and the Judge will make the call. Also, if you wait until the end of your cross-examination, and then tell the Judge you'd like to cross-examine the witness about external topics so that you don't have to recall her as your own witness on another day, the judge may agree, for the sake of judicial economy. If the judge refuses, you can ask that the witness be excused, subject to your recall. You can bring her back during your side of the case to ask her the questions you weren't allowed to ask during your cross-examination.