Recently, I was looking for the reviews of some Analysis books while encountered terms such as

Baby/Papa/Mama/BigRudin. Firstly, I thought that these are the names of a book! But it turned out that these are some nick names used for the books ofWalter Rudin. So I was thinking that1. What are the corresponding books of these nick names?

2. Why such nick names are chosen? or What are their origins?

**Answer**

In order to sum up the above comments, the corresponding books for these nick names are

1. Baby = Principles of Mathematical Analysis;

2. Papa/Big = Real and Complex Analysis;

3. Grandpa = Functional Analysis;

and it seems that the difficulty of contents of the books grows with the age of the nick names! Firstly, you are a baby and things are easy to handle. Then you grow up and become a papa and things get more complicated. Finally, when you are a grandpa you should take care of your legacy very carefully which needs a hardwork! So 1 is a prerequisite of 2 and 2 is prerequisite of 3.

**Attribution***Source : Link , Question Author : Hosein Rahnama , Answer Author :
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