Henry Mintzberg — Canadian Businessman born on September 02, 1939,

Henry Mintzberg, OC OQ FRSC is an internationally renowned academic and author on business and management. He is currently the Cleghorn Professor of Management Studies at the Desautels Faculty of Management of McGill University in Montreal, Quebec, Canada, where he has been teaching since 1968... (wikipedia)

Managers who don't lead are quite discouraging, but leaders who don't manage don't know what's going on. It's a phony separation that people are making between the two.
Companies are communities. There's a spirit of working together. Communities are not a place where a few people allow themselves to be singled out as solely responsible for success.
I describe management as arts, crafts and science. It is a practice that draws on arts, craft and science and there is a lot of craft - meaning experience - there is a certain amount of craft meaning insight, creativity and vision, and there is the use of science, technique or analysis.
You can teach all sorts of things that improve the practice of management with people who are managers. What you cannot do is teach management to somebody who is not a manager, the way you cannot teach surgery to somebody whose not a surgeon.
Basically, managing is about influencing action. Managing is about helping organizations and units to get things done, which means action. Sometimes, managers manage actions directly. They fight fires. They manage projects. They negotiate contracts.