Fisher is a crucial witness in this case because the government must present economic evidence that Microsoft has a monopoly power and used illegal tactics to keep it, in order to seek remedial action from the court at the end of the trial. Late yesterday, Microsoft lawyers began a cross-examination of Fisher that is expected to last most of the week. They'll counter his testimony with their own MIT economist, Richard Schmalansee. As the government prepared to wrap up its case, Boies also played a final portion of Microsoft CEO Bill Gates' combative deposition in front of Judge Thomas Penfield Jackson. As he did in other parts of the sparring session, the richest man in the world appeared to stonewall – claiming not to remember the policy, not to remember receiving e-mails from underlings about the policy and even professing not to understand the questions.