Charting the Higgs Boson Profile e+e- Linear Colliders

The problems of the origin of mass and of electro-weak symmetry breaking are central to the programme of research in particle physics, at present and in the coming decades. This paper reviews the potential of high energy, high luminosity e+e- linear colliders in exploring the Higgs sector,to extend and complement the data which will become available from hadron colliders. The accuracy of measurements of the Higgs boson properties will not only probe the validity of the Higgs mechanism but also provide sensitivity to New Physics beyond the Standard Model.