This volume, the fifth in the Encyclopedia of Indian Philosophies, is devoted to the philosophy of the grammarians. The introductory essay is intended to set their school in its context and to summarize the main grammarian teachings. The summaries of primary sources that follow the introduction aim at making available the substance of the main philosophical ideas contained in these works, so that philosophers who are unable to read the original Sanskrit and who find difficulty in understanding and finding their way about in the translations (where such exist) can get an idea of the positions taken and arguments offered. The summaries, then, are intended primarily for philosophers and only secondarily for indologists. Certain sections of the works have been omitted or treated sketchily because they are repetitions or deemed less interesting for philosophers, though they may be of great interest to Sanskritists. The summaries are not likely to make interesting consecutive reading: they are provided in the spirit of a reference work. The appendix, which contains a lengthy bibliography of original and secondary writings on the philosophy of grammar, is also presented as an aid to research.