There are two books by Kolmogorov & Fomin that I am interested in purchasing, namely Introductory Real Analysis and Elements of the Theory of Functions and Functional Analysis. Now, this will be my third book on graduate analysis; in particular, I have studied from Bartle’s Elements of Integration (which develops measure theory in an axiomatic/general sort of way) and a delightful little book called Introduction to Lebesgue Measure and Fourier Series by authors Wilcox and Myers (which develops the idea of Lebesgue measurable sets of the closed interval $[0,1]$, Lebesgue outer measure, and the Lebesgue integral). Next year, I will be starting graduate school; and, it appears that I will be using Royden or Rudin’s Real/Complex Analysis (but most likely Royden). As such, I am looking for one more text to tie everything together. So, I suppose my questions are as follows:
(1) Which of the two Kolmogorov & Fomin texts is better suitable for self-study?
(2) Which of the two Kolmogorov & Fomin texts contains topics most closely in line with the Royden text?
Thank you! Your input will be greatly appreciated. Note: I am also open to other suggestions assuming the cost of the text is low (or Frank Jones’s Lebesgue Measure on Euclidean Spaces would be an option).