Investigation of the interaction between the Higgs boson and the top quark is of high priority interest. The large mass of the top quark of approximately 173.3 GeV requires that it couples strongly to the Higgs boson in the SM. Consequently, the top quark is suspected to play a special role in the electroweak symmetry breaking. The Yukawa coupling of the top quark can be measured directly through the inclusive cross-section of the associated production of the Higgs boson with a top-quark pair (tt ̅H). The measurement of the Higgs boson production cross-section in association with a single top quark (tH) and the kinematic properties of tH and tt ̅H events can also provide information about the CP nature of the coupling. In the SM the Higgs boson is a scalar and its interactions are CP-even. The pure pseudoscalar hypothesis with CP-odd interactions with weak vector bosons and fermions has been excluded. However, it remains experimentally allowed that the Higgs boson is a CP-mixed state, which arises in extended Higgs sectors, and would provide a new source of CP-violation beyond the SM.