Venn's style is to take his readers very much into his confidence: as he builds the theory, he carefully points out the alternative paths he might have taken, the alternative definitions he might have used, he shows what the implications of these alternatives are, and justifies his choice on the broadest possible grounds.

What is distinctive about this work may be given in part in Venn's own words: “The thorough examination of symbolic logic as a whole, that is, in its relation to ordinary logic and ordinary thought and language; the establishment of every general symbolic expression and rule on purely logical principles, instead of looking mainly to its formal justification; and the invention and employment of a scheme of diagrammatic notation which shall be in true harmony with our generalizations.”