We are pleased to announce a monograph "Why must we work in the phase space?" (IPPT Reports 1/2016) by Jan J. Sławianowski, Frank E. Schroeck Jr., Agnieszka Martens. The authors are going to prove that the phase-space description is fundamental both in the classical and quantum physics. They have shown that many problems in statistical mechanics, quantum mechanics, quasi-classical theory and in the theory of integrable systems may be well-formulated only in the phase-space language. There are some misunderstandings and confusions concerning the concept of induced probability and entropy on the submanifolds of the phase space. First of all, they are restricted only to hypersurfaces in the phase space, i.e., to the manifolds of the defect of dimension equal to one. But what is more important, it was assumed there that the phase-space geometry was metrical-Euclidean and the resulting metric geometry of the microcanonical ensemble was obtained by the reduction of the primary Euclidean geometry to the corresponding submanifold. But it is well-known that the phase-space manifold has no natural metric geometry and that all concepts to be used must be of symplectic origin. Otherwise they are just accidental or artificial. So, instead the authors show that even if the configuration space is endowed with some metric, then in general the true geometry of submanifolds in the corresponding cotangent bundle (phase-space) is of different origin which has nothing to do with the mentioned configuration space Riemannian geometry, instead it is of purely symplectic origin. And this is sufficient to constructing microcanonical ensemble and entropy concepts. In any case, the purely symplectic phase-space geometry is sufficient to obtain everything within the completely metric-free language.