Re: Help me
Although the original topic is old, I would say there is no "best " book in math. Advanced Engineering Mathematics by Kreyszig is indeed an excellent excellent book for engineering mathematics, but it is in no way a good book for functional analysis. However, I second the suggestion of for Kreyszig's Introductory Functional Analysis with Applications. It is the book I used in my first functional analysis course and all I can say is it is a wonderful book for the subject.