Peter Drucker is often called the father of modern management. Many of the management books of today have borrowed from or elaborated on the ideas Drucker set forth in earlier decades. I recently had occasion to read The Essential Drucker, a compilation of many of the articles he has written spanning topics such as management and what a post-capitalistic society might look like.
Drucker was a man wise beyond his epoch. He foresaw a society where knowledge workers dominated the workforce, a phenomenon that many among us (including governments) seek to retard (through policies such as tariffs/incentives that favour manual employment). His writings are aimed at knowledge workers, providing a framework for dealing with the challenges and opportunities faced by this class.
For example, in the old economy, the efficient worker was effective. But for the knowledge worker, efficiency (doing things the right way) does not necessarily equate to effectiveness (doing the right things). The knowledge worker has to be equipped with the ability to determine what he *should* be doing, not just that he do it well.
Drucker lays out what he believes separates the effective knowledge workers from the ineffective. It is unrelated to personality type, upbringing, or intelligence in his view.
The effective manager understands that time is the one resource that is finite. He organizes himself so that he makes the best use of his time. He measures what he spends his time doing (which is far different than estimating what he *thinks* he spends his time doing) and adjusts appropriately so that he can be effective.
For all of Drucker's strengths in elaborating on management techniques, however, he lost me a bit on some of his views for how a society should take care of members who are unable to adapt. While I may agree with his argument that entitlement programs are bloated and ineffective at accomplishing their goals, his solution(s) doesn't seem plausible either. I won't spoil it for you, but I will hint that it does not involve government!
Overall, however, I would recommend the book to those looking for an intro to Drucker. For the management sections alone it is worth the read.