This volume presents some results of the work done in the matter of logical theory in the Department of Philosophy of the University of Chicago in the first decade of its existence. The eleven Studies are the work of eight different hands, all, with the exception of the editor, having at some period held Fellowships in this University, Dr. Heidel in Greek, the others in Philosophy. Their names and present pursuits are indicated in the Table of Contents. The editor has occasionally, though rarely, added a footnote or phrase which might serve to connect one Study more closely with another. The pages in the discussion of Hypothesis, on Mill and Whewell, are by him. With these exceptions, each writer is individually and completely responsible for his own Study.