Higgs boson. Complete discovery and the windiw to a New Physics

1. We discuss the opportunities of complete Higgs boson discovery at different colliders. Main conclusion here is: Photon collider is the best for this goal. 2. We discuss how to use the Higgs boson (after its discovery) as the window to a New Physics. Main conclusion here is: Higgs boson production in gluon and photon fusion together with production in process $e\gamma\to eH$ provides very good window to a New Physics with the scale $\Lambda\gg M_H$.