Obviously the first place to start here would be Max Weber‘s  “Sociology of Religion.” This is in English (PDF) and some people find texts like this are actually easier to understand in English, because the translator has unravelled the language for you.

He also wrote several monographs on why certain religions are suited to or produce certain social structures. The one on China summarizes his theory in the introduction.

• Africa
• China
• India

In addition, there was a rororo Monograph on Max Weber that is out of print but still available used. I’ve always found them to be well done and instructive. Or consult the Stanford Encyclopedia of Philosophy, which is online and free and quite thorough, or the Encyclopedia Britannica, which is briefer and has a free trial offer, just to get an overview. 

This is also an excellent place to start:

Andrew Greeley, Sociology and Religion. A Collection of Readings (click for overview)
(The readings are accompanied by papers discussing them.)

Andrew Greeley. Religion in Europe an the end of the Second Millennium
                           ( Here he analyzes surveys conducted by others and collates them.) 

There is a big difference between the classical approach of narrative description and the current sociological approach, based on statistics. With the latter, you are still faced with trying to figure out what the variations mean and whether you have omitted relevant variables. And with the former, you risk infecting the data with your own preconceptions, as Weber arguably did, deciding that Calvinism drove the market and then setting out to prove it. But sociology is essential for planning. You cannot move or accommodate to a social trend, unless you understand what is behind it, sustaining and directing it.

Alain de Botton, Religion for Atheists

Religion for Atheists

What if religions are neither all true or all nonsense? The boring debate between fundamentalist believers and non-believers is finally moved onwards by Alain’s book Religion for Atheists, which argues that the supernatural claims of religion are, of course, entirely false – and yet that religions still have some very important things to teach the secular world.

This (below) belongs under philosophy, but as long as you’re reading de Botton, you might like to check this out as well.

This should be available in German.