Arrow keys, left and right:  Moves the cursor left and right.  When a portion of the sound is selected, moves the cursor to the start or end of the selection.  When the option key is held down, moves the cursor to the start or end of the sound.  When the shift key is held down,  the selection is lengthened.

Arrow keys, up and down:  Used to zoom in and out on the sound.  Up is zoom out and down is zoom in.

Space Bar:  Plays the sound and stops playing or recording.

Clear key:  Deletes the current selection of a sound or envelope.

Delete key:  Deletes the current selection of a sound or envelope.

Option key:  Command-Option-A sets the selection to none.
                       Command-Option-F fits the sound.
                       Command-Option-P plays the loop.
                       Command-Option-R overdubs.
                       Command-Option-W closes all windows.
                       See "Controls".
                       See "Preferences".
                       Toggles the selection of a track when clicking on the track.
 
Control key:  Selects all of the tracks when clicking on the track.

Shift key:  Adjusts the selection when clicking on the sound window instead of selecting nothing.

Caps Lock key:  The Length field shows the length of the selection instead of the sound.

Tab key:  Toggles between the start and end of the selection if its wider than the window, otherwise it centers the selection or cursor in the window.