So says Ed Harris, the MIB-style figment of Russell Crowe's imagination, when the latter screams: "You're not real! You're not real!"

This is a biopic of Nobel Prizewinner John F Nash, the mathematical genius who thought up the Nash Equilibrium, a major contribution to Game Theory. Poor Nash became afflicted with paranoia-schizophrenia, a condition he suffered from for about two decades until the symptoms abated.

Cleverly, Ron Howard introduces us gradually to Nash's unreal world.The effects - such as an umbrella star constellation and magazine pages that light up etc, are wonderfully done.

On the downside, the historical facts are played around with, when the facts would probably make a better story. (For example, the Equilibrium was not instantly accepted,unlike shown in the film.)

Russell Crowe's performance is not particularly good. Jennifer Connelly's is much better as the just-too-good-to-be true girlfriend, then wife.

At the pen-laying ceremony at the end, I was expecting Ed Harris to come and lay his pen, but I suppose that is just the way I look at the world.