Tuning
Tenor guitars are normally tuned in fifths (usually CGDA, similar to the tenor banjo or the viola) although other tunings are possible, such as "guitar tuning", "Chicago tuning," or baritone ukulele tuning (DGBE), "Irish" or "octave mandolin" tuning (GDAE, like a violin but one octave below) and various "open" tunings, for slide playing. The tenor guitar can also be tuned like a soprano/concert/tenor ukulele, using various versions of GCEA tuning.
The normal CGDA tuning is very "open" and it gives the instrument unusual voicings from both open and closed chords. The fifths tuning also makes for easy moveable chord shapes. The instrument is equally well suited to both rhythm and lead playing.
Though books are available for the standard tunings above, books are also available for more esoteric tunings as well such as GDAD, CGBD and DGBE in the Chord Genius series of books published by Northern Musician Services. One of the main attractions of this instrument is its breadth of available tunings.
Read more about this topic: Tenor Guitar