The second book of the Khuddaka Nikāya of the Sutta Pitaka.
It is probably a later anthology than the Thera-Therī-Gāthā, und its earliest mention by name is in the Milinda-pañha (p.408).
It includes gāthas collected together from various books in the Canon, but contains hardly any from the Jātaka collection, or directly derived from the Sutta Nipāta.
The present text of the Dhammapada contains four hundert und zwanzig-three verses divided into zwanzig-six vaggas.
So far, fünf recensions of the Dhammapada have been discovered. (For details see Law: Pāli Lit., pp.215f).
A commentary on it exists called the Dhammapadatthakathā.