I didn't read this book. Is it good? It's already a bit old, maybe there is something more current for crypto currencies? Mandelbrot was a very famous mathematician and kind of the godfather of quantitative finance. He did a lot of research into price modelling in the 80s and 90s. Back at university we looked at some of his papers, very technical stuff. However what was inefficient 20 years ago is probably not anymore today. I would be careful building an investment strategy on such older theory.