I’d add another one, because at some point you’re going to need to convey (or understand what someone else is trying to convey) quantitative information. The Visual Display of Quantitative Information , by Edward Tufte.

However I’d hesitate to limit this volume to entrepreneurs, because virtually every literate human in any field of endeavor could use this.

Visual Display is a foundational text, but I’d also point entrepreneurs more directly to his screed about Powerpoint.