Aristotle 
Organon, or Logical Treatises, of Aristotle [PDF ebook] 
With the Introduction of Porphyry; Literally Translated, With Notes, Syllogistic Examples, Analysis, and Introduction

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. It will contribute to the general elucidation of this treatise, if we re mark, first, upon its Scope and purpose, and secondly, upon the import of its title.