How to Study for a Mathematics Degree is for intending and current undergraduates in UK-style higher education systems where people specialise early and begin studying proof-based mathematics on entry to university.  How to Study as a Mathematics Major is a slightly adjusted version for students in US-style systems where people specialise later and (usually) begin studying proof-based mathematics in their sophomore or junior year.  Wie man erfolgreich Mathematik studiert is a German translation.  How to Think about Analysis is a prequel or accompanying text to a course on real analysis or advanced calculus.  It explains the key ideas in depth, and will soon be translated into Japanese.  See also the reviews of both books.