MusE is a MIDI/Audio sequencer with recording and editing capabilities written originally by Werner Schweer now developed and maintained by the MusE development team. MusE aims to be a complete multitrack virtual studio for Linux. It is published under the GNU General Public License.
Visit the MusE web site at: http://www.muse-sequencer.org
Most Linux distributions include MusE ready to install, check your package manager.
Installation from source code:
Stable source code releases are here. Or one of the git branches can be cloned, built, and installed.
These and other important documents, READMEs, and addendums are in the muse3 directory.
The official MusE manual can be found here in HTML or PDF form in the muse3/doc directory. The manuals are also installed along with MusE.