John J. Mortensen is a leader in the revival of historic improvisation. He is noted for his ability to improvise entire concerts. He frequently teaches and performs internationally. He is the author of The Pianist's Guide to Historic Improvisation, now in use as a course text at many leading conservatories. He is the creator of Improv Planet, an online school of historic improvisation, where his students include concert artists and conservatory faculty from across the world.