If you asked me before I had seen this film if I thought Russell Crowe was capable of acting this role, I would have had serious doubts. Now that I have seen it, I can only say that Russell Crowe's portrayal of John Nash is one of the most deserving of an Oscar that I have ever seen! The film is based on the life of John Nash, a brilliant mathematician who struggled with mental illness for much of his life. There is a large injection of fiction into the story, but it is done in a way that is wholly believable. As usual, Hollywood insists on adding a love story, but this one is not too sugary, and the excellent performance of Jennifer Connelly makes this a very moving film, with an ending that you spend the whole film hoping for. Crowe's performance is so believable, especially when he is in the depths of his illness. The rest of the supporting cast do a fine job too, and Ron Howard's direction is the right balance of seeing the illness both from the inside and the outside. A five star performance from Crowe!