A Course of Modern Analysis (colloquially known as Whittaker and Watson) is a landmark textbook on mathematical analysis written by E. T. Whittaker and G. N. Watson, first published by Cambridge University Press in 1902. (The first edition was Whittaker's alone; it was in later editions with Watson that this book is best known.)
The book is notable for being the standard reference and textbook for a generation of Cambridge mathematicians including Littlewood and G. H. Hardy. Mary Cartwright studied it as preparation for her final honours on the advice of fellow student V.C. Morton, later Professor of Mathematics at Aberystwyth University. But its reach was much further than just the Cambridge school; André Weil in his obituary of the French mathematician Jean Delsarte noted that Delsarte always had a copy on his desk.
Today, the book retains much of its original appeal. Some idiosyncratic but interesting problems from the salad days of the Cambridge Mathematical Tripos are to be found in the exercises. It is terse, yet readable by the motivated student. It conforms to high standards of mathematical rigour, while compressing much actual formulaic information also.
The book was one of the earliest to use decimal numbering for its sections, an innovation the authors attribute to Giuseppe Peano.