Denemo helps prepare notation for publishing and lets a user rapidly enter notation for typesetting via the GNU LilyPond music engraver. Music can be typed in using a PC keyboard, taken from MIDI input, or played into a microphone plugged into a soundcard. Denemo itself does not engrave the music - it functions as a GUI for LilyPond. Denemo only displays the music so a user can enter and edit it efficiently. This program includes scripts to run music tests and practice exercises for educational purposes. This program plays back via an Internal Sampler and can act as a JACK/MIDI client.