Books like The Infinity Concerto

There is a song you dare not sing - a melody that you dare not play, a concerto that you dare not hear: It is called a Song of Power. It is a gateway to another world - a gate that will lock behind you as you pass, barring you from the Earth forever. Resist at all cost. For it is a world of great danger and great beauty - and it is not good to be human in the Realm of the Sidhe.