user16626: According to Wikipedia, the former world champion Tigran Vartanovich Petrosian has "almost impenetrable defensive playing style, which emphasized safety above all else". 
Here defensive is by no means passive and emphasizing safety above all else is surely not a bad thing (see Petrosian's accomplishments). Which book would you recommend, if one wishes to play like Petrosian?

user657: Shektman has a great two-volume set on Petrosian's games, but really, to play like Petrosian you need to get very good at tactics. One of the secrets to his playing style was the way he could sniff out the tactical possibilities inherent in the position and defang them before his opponent could take advantage of them. Daniel Naroditsky wrote a little something about that at https://www.chess.com/article/view/petrosians-tactical-side
Something to play close attention to in his games are the rooks; he was a master of the exchange sacrifice.
Maybe a good book for starters would be Petrosian, Move By Move, by Thomas Engqvist. It takes a look at several of his games and tries to explain every single move. 

user4418: Petrosian's Best Games of Chess 1946-63 by P.H. Clarke, published by Bell & Sons is the obvious place to start.

user12873: One of Petrosian's greatest strengths was his prophylactic thinking; i.e., identifying threats before they arise and neutralizing them. A book which discusses this concept would be good. For example, "Recognizing Your Opponent's Resources: Developing Preventive Thinking".
If you want to learn more about Petrosian himself, part 3 of Kasparov's My Great Predecessors series would be good. In this book he goes over the games of Spassky and Petrosian.

16626: <p>According to <a href="https://en.wikipedia.org/wiki/Tigran_Petrosian" rel="nofollow noreferrer">Wikipedia</a>, the former world champion Tigran Vartanovich Petrosian has "almost impenetrable defensive playing style, which emphasized safety above all else". </p>

<p>Here defensive is by no means passive and emphasizing safety above all else is surely not a bad thing (see Petrosian's accomplishments). Which book would you recommend, if one wishes to play like Petrosian?</p>
 657: <p>Shektman has a great two-volume set on Petrosian's games, but really, to play like Petrosian you need to get very good at tactics. One of the secrets to his playing style was the way he could sniff out the tactical possibilities inherent in the position and defang them before his opponent could take advantage of them. Daniel Naroditsky wrote a little something about that at <a href="https://www.chess.com/article/view/petrosians-tactical-side" rel="nofollow noreferrer">https://www.chess.com/article/view/petrosians-tactical-side</a></p>

<p>Something to play close attention to in his games are the rooks; he was a master of the exchange sacrifice.</p>

<p>Maybe a good book for starters would be Petrosian, Move By Move, by Thomas Engqvist. It takes a look at several of his games and tries to explain every single move. </p>
 4418: <p><a href="https://rads.stackoverflow.com/amzn/click/com/0713502061" rel="nofollow noreferrer" rel="nofollow noreferrer">Petrosian's Best Games of Chess 1946-63</a> by P.H. Clarke, published by Bell &amp; Sons is the obvious place to start.</p>
 12873: <p>One of Petrosian's greatest strengths was his prophylactic thinking; i.e., identifying threats before they arise and neutralizing them. A book which discusses this concept would be good. For example, "Recognizing Your Opponent's Resources: Developing Preventive Thinking".</p>

<p>If you want to learn more about Petrosian himself, part 3 of Kasparov's My Great Predecessors series would be good. In this book he goes over the games of Spassky and Petrosian.</p>
