This textbook leads the reader by easy stages through the essential parts of the theory of sets and theory of measure to the properties of the Lebesgue integral.

Ralph L. Jeffery (1889-1975) was the head of the Mathematics Department at Queen's University for 18 years until his retirement in 1960.

"At times brings the reader close to the frontiers of knowledge in this field"

"Many interesting topics are treated in this book. Moreover, the presentation is very careful and readable."

"There is about this book a refreshing air of personality. A reader brought up on other accounts of this theory, even written from the same point of view, will find many points of novelty."