D. Shivakumar, chairman and chief executive officer (CEO) of PepsiCo India Holdings Pvt. Ltd, is an affable man. Behind the affable exterior is a thoughtful professional who frets that “why companies fail" is among the most researched topics on the Internet.

Shivakumar isn’t a proponent of companies building a “strong culture". Unlike many of his contemporaries, he finds the idea disconcerting. “Strong cultures hurt companies," he says.

As much as it sounds counter-intuitive, he’d much rather strive towards an “enabling culture". Because, he argues, “companies with strong cultures cannot adapt. Henry Ford built a strong culture. It came back to haunt and hurt him. Companies with enabling cultures allow you to learn, accept failure and move on."

Shivakumar’s passion is such that he maintains a ravenous appetite for learning and devours on average at least two books every week.

People close to Mukesh Ambani, chairman of Reliance Industries Ltd, and among the richest men in the world, speak in awe of his ability to consume incredible amounts of literature on various themes. If they are to be believed, he spends a good part of his nights in his personal library, reading up on pretty much everything he can get his hands on.

Shane Parrish, a Canadian entrepreneur and CEO of Farnam Street Media Inc., discovered much the same thing about legendary investor Warren Buffett, who spends 80% of his time reading and thinking.

Only 20% of Buffett’s time, it seems, goes into what is conventionally called work. On Parrish’s passionately maintained Farnam Street blog, he writes: “Most people go through life not really getting any smarter. Why? They simply won’t do the work required. It is easy to come home, sit on the couch, watch TV and zone out until bedtime rolls around. But that’s not really going to help you get smarter.

“Sure you can go into office the next day and discuss the details of last night’s episode of Mad Men or Game of Thrones. And, yes, you know what happened on Survivor. But that’s not knowledge accumulation; it’s a mind-numbing sedative. But you can acquire knowledge if you want to. In fact, there is a simple formula, which if followed is almost certain to make you smarter over time. Simple, not easy.

“It involves a lot of hard work. We’ll call it the Buffett formula, named after Warren Buffett and his longtime business partner at Berkshire Hathaway, Charlie Munger… They are learning machines… They didn’t get smart because they are both billionaires. No, in fact they became billionaires, in part, because they are smart. More importantly, they keep getting smarter. And it turns out they have a lot to say on the subject. How to get smarter? Read. A lot," he writes.

Parrish talks of the time when somebody asked Buffett how to get as smart as him. He held up a stack of paper and said, “Read 500 pages like this every day. That’s how knowledge builds up, like compound interest."

That is also why, between the two of them, when it comes to decision-making, it is in split seconds. They don’t have to expend energies analysing the problem. The knowledge required to make the decision is already embedded in their psyche.

That is why it is important to ask how these men read.

“Only the lazy don’t make the time to read," says Shivakumar.

So, as much as the title may sound humiliating and the kind you don’t want to be seen with, How to Read a Book by Mortimer Adler is a must-have. A classic first published in the 1940s, an updated version of the book is now available. It articulates in excruciating detail how to deal with books and get the most out of them.

The sum and substance of Adler’s argument is that there are four levels of reading.

1. Elementary reading any literate person is familiar with.

2. Inspectional reading where time is placed as a constraint.

3. Analytical reading that places demands on the reader, requires attention, doesn’t have time as a constraint.

4. And finally, there is syntopical reading. “When reading syntopically, the reader reads many books, not just one, and places them in relation to one another and to a subject about which they all revolve. But mere comparison of texts is not enough… With the help of the books read, the syntopical reader is able to construct an analysis of the subject that may not be in any of the books. It is obvious, therefore, that syntopical reading is the most active and effortful kind of reading."

Readers like Buffett, Ambani and Shivakumar begin by inspecting the book. They check whether it’s worth their time or not by skimming over the cover, inner flap, table of contents and preface. If it merits attention, they get into it.

In doing that, they classify the book in their head depending on the theme it addresses and define the problem the author is attempting to solve. But they are smart enough as well to know that one author does not have all the answers to the questions they may have in mind.

More importantly, reading multiple authors on any given theme provides multiple perspectives on an issue. This is why they inevitably have informed and intelligent opinions.

In doing all of this, Adler suggests that readers apply a few filters to the literature on their minds, particularly when it comes to current events:

1. What does the author want to prove?

2. Whom does he want to convince?

3. What special knowledge does he assume?

4. What special language does he use?

5. Does he really know what he is talking about?

And finally, Parrish insists that the involved reader use the Feynman Technique, named after the physicist Richard Feynman, to learn and retain all that is in the book. This involves four steps.

1. Choose the concept you want to understand.

2. Pretend you’re teaching the idea to someone else.

3. If you get stuck, go back to the book.

4. Simplify your language.

Shivakumar practises this diligently. Every fortnight, he makes a deck out of the books he reads and summarizes it in 30-40 odd succinct slides. He then sends it out to all of PepsiCo’s employees and roughly 150 other people on his mailing list he thinks may find it interesting. When asked why he does it: “I’m not Bill Gates who can practise philanthropy. This is my way of giving back a part of what I earn."

Charles Assisi was managing editor at Forbes India and is at work on his first venture. He maintains a personal website on www.audaciter.net and tweets on @c_assisi