Human Sigma: Managing the Employee-Customer Encounter

This was an extremely dense book, but useful. The learnings in this book would take years to put into place, even at a company that is already prepared to do so. With that, I'd say this is probably a text to revisit over and over again, and perhaps only super valuable at the executive level or at a small, flat startup. You would need to have organization buy-in to put these things in place.