Finite temperature and chemical potential in lattice QCD and its critical point

We propose a method to study lattice QCD at finite temperature (T) and chemical potential (\mu). We compare the method with direct results and with the Glasgow method by using n_f=4 QCD at Im(\mu)\neq0. We locate the critical endpoint (E) of QCD on the Re(\mu)-T plane. We use n_f=2+1 dynamical staggered quarks with semi-realistic masses on L_t=4 lattices. Our results are based on {\cal{O}}(10^3-10^4) configurations.