Maybe a bit late to comment, but for what it's worth: There is no primer that could be actually useful, because the "tax optimization" landscape is fragmented and constantly shifting. Everything depends on where you live, where you do business, how much much money is involved, etc.
But there is a central driving force behind it all: governments constantly fight for "tax justice" with one hand and create various "incentives" and exceptions with the other, in an effort to briefly gain the upper hand over other countries in the zero-sum game of attracting international capital. The former tends to plug all possible loopholes for the "ordinary wealthy", while the latter always leaves options for the truly big fish, they just don't stay the same decade-over-decade.
But there is a central driving force behind it all: governments constantly fight for "tax justice" with one hand and create various "incentives" and exceptions with the other, in an effort to briefly gain the upper hand over other countries in the zero-sum game of attracting international capital. The former tends to plug all possible loopholes for the "ordinary wealthy", while the latter always leaves options for the truly big fish, they just don't stay the same decade-over-decade.