It is indeed a mathematically excellent series of books. Unfortunately, a textbook chiefly functions as a tool for the teacher to use, and if the culture for which the book is designed doesn’t match that of the teacher, the results are not likely to be successful. This was among the conclusions of the 2005 PCMI International Seminar, whose participants included some from Singapore. Their very thoughtful conclusions can be found at Mathematics Education Around the World: Bridging Policy and Practice, under "2005 Policy Recommendations". Note also the comment in Newsweek by the Singapore minister of education: "Recently, Newsweek International's Fareed Zakaria noted Singapore's success on international math and science exams, but asked Education Minister Tharman Shanmugaratnam why Singapore produced so few top-ranked scientists, entrepreneurs, inventors, business executives and academics. "We both have meritocracies," he replied. America's "is a talent meritocracy, ours is an exam meritocracy. There are some parts of the intellect that we are not able to test well -- like creativity, curiosity, a sense of adventure, ambition. Most of all, America has a culture of learning that challenges conventional wisdom, even if it means challenging authority. These are the areas where Singapore must learn from America."