What does "master" mean? As I read both English and Russian chess literature I run into the term 'master'. It is clear from the context that is below grandmaster but is somehow given much respect. I never know what it actually means because it could be any of the three or even something else: FIDE Master, International Master, National Master (whose meaning depends on the country).

This site has many questions about 'master strength' so it is part of everybody's jargon. But I really don't know what it means.
There are several reasons why someone would use the term 'master', but without a specific reference to work from all I can suggest is that the term is generally synonymous with the phrase 'top player'. The two examples that come to mind are:


Historical: Many of the great early players did not have actual titles (either because the titles had not been invented or because the systems for reliably attaining them had not been introduced). In this case, one might refer to Morphy or Philidor as a 'master', simply because calling them a GM/IM would be inaccurate. Also consider that when the title 'Grand Master' was first conferred, it was not just a title to hand out to players but a real statement that those five players were some of the best ever. 
Cultural: As you noted in the question, many foreign (esp. Russian) books up until the 1980s or so use the term. I cannot say exactly why, but the usage is certainly meant to indicate that those people are deserving of respect as top-calibre players. Perhaps part of this is due to the fact that some top theoreticians were not acknowledged as being among the best practical players, and so this allowed them to be given the same level of respect as determined by the author. Hopefully someone more knowledgable in soviet chess culture can fill us in on this one.


This is in contrast to the modern USCF system where a range of various master titles are (by comparison to earlier times and other areas of the world) given out like candy. This is not to say that the achievements are not still somewhat impressive, but they ultimately mean something much less than the term does in those other contexts.