| We analyze available experimental data on the phase diagram of High Tc-cuprates, for single-layered materials, mainly, which currently are better studied by diverse techniques. At higher temperatures in the (T,x)-plane data for LSCO can be interpreted in terms of a 1st order phase transition frustrated by the Coulomb interactions. We argue that this phase transition is led by charge (lattice/polaronic) degrees of freedom. We estimated the onsets of transitions for charge and spin degrees of freedom from the NMR and the Hall data to obtain the x-dependence of the hypothetical first order transition. The obtained T*(x) is basically the same as the line for the "pseudogap crossover" defined from other experiments. In particular, it turns out that in the "pseudogap" regime the 63^ Cu-nuclear spin relaxation is the sum of two independent relaxation processes, one of which is related to "stripes". Such interpretation becomes less transparent at lower temperatures, where numerous phases compete for the ground state(superconductivity being only one among them).We summarize results from transport, NMR and muSR, neutron scattering experiments and some others, to clarify the sequence of phases with doping increase and ranges of their coexistence. It is worth mentioning that even at low temperatures transition into sub-phases are driven by the charge(lattice) variables. |