The question about the existence of open book decompositions for a closed oriented $n$-dimensional manifold seems to be answered in all dimensions except dimension $4$, where as far as I can tell the situation seems to be quite mysterious. By playing around with the definition one can see that the signature has to vanish and the Euler characteristic has to agree with the Euler characteristic of a surface. Since the situation does not seemed to be resolved yet, these are probably not the only restrictions.
So my questions are:
What is the state of the art about open book decompositions in dimension $4$?
Do there exist requirements that ensure that a $4$-manifold admits an open book decomposition
Do there exist requirements that ensure that a $4$-manifold admits an open book decomposition up to stabilization i.e. connected sum with certain other $4$-manifolds
As a non-trivial example, does the product of two surfaces of genus at least $2$ admit an open book decomposition? Does it admit one up to stabilization?