Emanuel Lasker, PhD (December 24, 1868 – January 11, 1941) was a German chess player, mathematician, and philosopher who was World Chess Champion for 27 years (from 1894 to 1921). In his prime Lasker was one of the most dominant champions, and he is still generally regarded as one of the strongest players ever. In 1906 he published a booklet titled Kampf (Struggle), in which he attempted to create a general theory of all competitive activities, including chess, business and war.
This is a book that is hard to read because Lasker came up with idealised or perfect versions of existing phenomena and gave them new names but didn't bother to explain them in detail. Of course that does not mean the book is not worth reading, it is quite the opposite. Even though the book is more than a century old, most of Lasker's ideas are still very fresh and applicable. The practical aspects of his ideas make this book a good one in the self-help category in my opinion.
This is must-have-been-had years ago. Found russian pirate translation on my old kindle and couldn't go sleep before finishing the piece. It's awesome. It's cruel. It's punishing and smart. Read it, if you're Ukrainian.