There are no solution manuals. For self-study, this is a massive hurdle. If you get stuck on a problem, you are on your own (except for forums like Math StackExchange).

You cannot buy a new copy. Used hardcovers on Amazon/AbeBooks start at $150-$300+. This is the primary reason people seek the PDF.

: Explores abstract measure theory and its relevance to analysis. Calculus Rigor

For students transitioning from the "plug-and-chug" methods of elementary calculus to the deep, rigorous waters of real analysis, the works of Gabriel Klambauer

It was a chilly winter evening when Alex, a graduate student in mathematics, stumbled upon a treasure trove of mathematical knowledge. While browsing through an online repository of mathematical texts, Alex came across a PDF of Gabriel Klambauer's "Mathematical Analysis". The book, first published in 1975, had been a classic in the field of mathematical analysis for decades.