By Paul R. Halmos
"This booklet is a truly really good yet extensively priceless creation to set concept. it truly is geared toward 'the starting scholar of complicated arithmetic' … who desires to comprehend the set-theoretic underpinnings of the math he already is aware or will examine quickly. it's also precious to the pro mathematician who knew those underpinnings at one time yet has now forgotten precisely how they cross. … a very good reference for the way set thought is utilized in different components of mathematics." — Allen Stenger, The Mathematical organization of America, September 2011.