This book, "An Introduction to the Theory of Numbers" by Prof. G. H. Hardy and Prof. E. M. Wright, is a highly regarded work in the Oxford series on pure mathematics. It has been updated for its second edition, making substantial changes to the text. The theory of quaternions has been rewritten using Hurwitz' method, and the chapter on the geometry of numbers has been completely revised based on suggestions from Prof. Davenport. The book is accessible to a wide range of mathematical readers, offering elementary discussions of problems that have taken mathematicians much of their lives to solve. Despite some criticism that these problems are not important, they are valuable for their educational and recreational value. This book, "The Population of Great Britain: Current Trends and Future Problems" by Mark Abrams, is part of a series by the Research Department of the London Press Exchange. It provides a careful collection and presentation of facts about the decline in the birth rate and the proposed remedies. The book includes new vital statistics from the 1938-1939 period, making it a useful resource for understanding post-war demographic issues in British industry and commerce. This short study by I. Bernard Cohen, "Roemer and the First Determination of the Velocity of Light," explores Roemer's observations on Jupiter's moon that led to the discovery of the finite speed of light. The book details Roemer's background, his initial reception, and his later career. It includes facsimile reproductions of Roemer's original papers and a holograph manuscript of his observations, providing a scholarly appreciation of a significant but often overlooked figure in science. This treatise on theoretical and physical chemistry by Georges Champetier is known for its clear and readable style. It covers fundamental concepts such as chemical species, mixture, compound, and element, as well as more advanced topics like band spectra, bond formation, and nuclear physics. The book is well-structured and accessible, making it a valuable introduction to modern physical and theoretical chemistry. This book, "Modern Bird Study" by Ludlow Griscom, is based on a series of lectures given at the Lowell Institute in 1944. The first half discusses the capacity, intelligence, and adaptability of birds, as well as migration, while the second half focuses on avian distribution in the Americas. Griscom's enthusiasm for his subject is evident, but the book could benefit from more rigorous inductive reasoning.This book, "An Introduction to the Theory of Numbers" by Prof. G. H. Hardy and Prof. E. M. Wright, is a highly regarded work in the Oxford series on pure mathematics. It has been updated for its second edition, making substantial changes to the text. The theory of quaternions has been rewritten using Hurwitz' method, and the chapter on the geometry of numbers has been completely revised based on suggestions from Prof. Davenport. The book is accessible to a wide range of mathematical readers, offering elementary discussions of problems that have taken mathematicians much of their lives to solve. Despite some criticism that these problems are not important, they are valuable for their educational and recreational value. This book, "The Population of Great Britain: Current Trends and Future Problems" by Mark Abrams, is part of a series by the Research Department of the London Press Exchange. It provides a careful collection and presentation of facts about the decline in the birth rate and the proposed remedies. The book includes new vital statistics from the 1938-1939 period, making it a useful resource for understanding post-war demographic issues in British industry and commerce. This short study by I. Bernard Cohen, "Roemer and the First Determination of the Velocity of Light," explores Roemer's observations on Jupiter's moon that led to the discovery of the finite speed of light. The book details Roemer's background, his initial reception, and his later career. It includes facsimile reproductions of Roemer's original papers and a holograph manuscript of his observations, providing a scholarly appreciation of a significant but often overlooked figure in science. This treatise on theoretical and physical chemistry by Georges Champetier is known for its clear and readable style. It covers fundamental concepts such as chemical species, mixture, compound, and element, as well as more advanced topics like band spectra, bond formation, and nuclear physics. The book is well-structured and accessible, making it a valuable introduction to modern physical and theoretical chemistry. This book, "Modern Bird Study" by Ludlow Griscom, is based on a series of lectures given at the Lowell Institute in 1944. The first half discusses the capacity, intelligence, and adaptability of birds, as well as migration, while the second half focuses on avian distribution in the Americas. Griscom's enthusiasm for his subject is evident, but the book could benefit from more rigorous inductive reasoning.