Peter Drucker first published this book in 1967, and it has aged better than almost anything written about management since. Drucker — the man who coined the term "knowledge worker" in the 1950s — argued something genuinely radical for its time: effectiveness is not a talent you are born with, it is a habit, a set of practices, and practices can be learned. The book lays out 5 of them. Below are those principles in my own words, plus why each one matters when you are the person responsible for results.
The single sentence that anchors the whole book: an effective executive gets the right things done. Efficiency is doing things right; effectiveness is doing the right things. You can be flawlessly efficient at work that should never have been started.
Drucker's first practice is the least glamorous and the most overlooked: time is the one resource you cannot buy more of, and most people have no idea where theirs actually goes. The discipline is to record your time honestly (not from memory, which lies), then prune the waste, then consolidate what is left into large uninterrupted blocks. Drucker estimated a typical executive could consign something like 25 percent of their time demands straight to the wastebasket without anyone noticing.
Why it matters in business: Fragmented time produces fragmented work. A founder who context-switches every fifteen minutes never does the deep, unglamorous thinking that actually moves the company. Track a real week, kill the meetings and reports nobody reads, and defend a daily block for the work only you can do.
The effective person asks "What results are expected of me?" and "What can I contribute that genuinely matters?" — not "What work do I have to do?" or "What does my title entitle me to?" The orientation is toward the outside: the customer, the result, the organization's purpose. The ineffective person mistakes effort and busyness for contribution.
Why it matters: Activity is the great disguise for a lack of results. A team can be exhausted and still be contributing nothing the customer would pay for. Force every role — including your own — to name the one or two outputs that would make a real difference, and judge effort against those, not against hours logged.
Effective executives staff and decide for strength. They ask "What can this person do uncommonly well?" rather than "What are they bad at?" That goes for hiring subordinates, managing up to a boss, and being honest about their own makeup. You do not build performance by patching weaknesses up to mediocre; you build it by making strength productive and rendering weakness irrelevant.
Why it matters: Hiring to eliminate flaws produces a team of inoffensive average performers. Hiring for one outstanding strength and tolerating the irrelevant weaknesses around it produces excellence. The same logic applies to you: spend your energy where you are genuinely exceptional and find people to cover the rest.
Effective people do one thing at a time, and they do the most important thing first. Concentration is forced because there is always more worthy work than time. That means setting priorities, and — harder — setting posteriorities: the deliberate list of things you will NOT do. Drucker's rule for choosing was to pick the future over the past, opportunity over problem, your own direction over the bandwagon, and the high-aim over the safe-and-easy.
Why it matters: The default failure mode of capable people is doing many things slightly. The discipline of finishing one thing before starting the next, and abandoning yesterday's priorities that no longer fit, is what separates a company that ships from one that is perpetually "almost there."
Drucker argued that effective executives make few decisions — but big, fundamental ones, solved at the level of the underlying principle rather than the symptom of the day. A sound decision starts by defining the boundary conditions (what must this solve?), insists on disagreement before commitment (consensus reached too easily means nobody really thought), and builds the action and feedback to execute it into the decision itself. A decision that nobody is assigned to carry out is just a good intention.
Why it matters: A flood of small, reactive decisions is a symptom of treating recurring problems as one-off events. Solve the generic problem once with a rule, reserve real deliberation for the rare fundamental choice, and never confuse the decision with its execution — the work begins when the meeting ends.
The throughline is unfashionable but durable: manage yourself before you manage others, get the right things done rather than many things, and treat effectiveness as a skill you practice — not a gift you wait for.
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Attribution: principles drawn from Peter F. Drucker, "The Effective Executive: The Definitive Guide to Getting the Right Things Done" (Harper & Row, 1967). Drucker's own condensed treatment appears in his Harvard Business Review article "What Makes an Effective Executive" (2004). The summary and commentary above are original.