The fifth-century grammarian-philosopher Bhartṛhari has long attracted scholarly attention, and deservedly so: his magnum opus, the Vākyapadīya, had a profound impact on later Indian schools of thought, Brahmanical as well as Buddhist. The Vākyapadīya is not, however, the only grammatical and/or philosophical work ascribed to Bhartṛhari in addition to a commentary on Patañjali’s Mahābhāṣya: according to several sources dating back at least to the tenth century, the same author also composed a Śabdadhātusamīkṣā or Ṣaḍdhātusamīkṣā that, unfortunately, has not come down to us, and that is still shrouded in mystery as its main topic, and even title and attribution, are considered uncertain to date. The goal of this article is to examine the available fragments and testimonies and to establish on their basis that the work, the original title of which must have been the Ṣaḍdhātusamīkṣā, endeavored to show that the whole phenomenal world is made of six elements (earth, fire, water, air, ether and consciousness) while ultimately defending a nondualistic point of view. Verses quoted by later authors as belonging to the Ṣaḍdhātusamīkṣā are gathered and translated in an appendix to the article. (https://paris3.academia.edu/IsabelleRati%C3%A9)