There's a fascinating short companion (of sorts) to this, which is a MathOverflow question written by Gowers: http://mathoverflow.net/questions/58061/how-can-th

There's a fascinating short companion (of sorts) to this, which is a MathOverflow question written by Gowers: http://mathoverflow.net/questions/58061/how-can-there-be-topological-4-manifolds-with-no-differentiable-structure/59406 http://mathoverflow.net/questions/58061/how-can-there-be-top...