Hello everybody. I'm reading My System by Nimzovich and so far it's been a great book until I reached the part 2. I do not understand the part about the Doubled pawns. (Chapter 2 Doubled Pawns and Restraint). Are you supposed to make your opponent doubled pawns advance? What happens after you make it advance? And I also do not get the whole "Active/Dynamic vs. Static/passive" part. Would somebody be so kind as to explain it to me? Thanks so much.

History:
The book came from four monographs.
The original version was in German.
Wikipedia indicates only a few of the English language version.
See:
This list is incomplete; you can help by expanding it.
The original German edition was published in 1925. This edition is out-of-print.
In 1930, a British English edition titled My System, translated by Philip Hereford, was published by Harcourt, Brace and Company. This edition is out-of-print.
In 1987, B.T Batsford Ltd, London reprinted the 1929 edition by Philip Hereford, entitled My System A Chess treatise by Aron Nimzowitsch. (ISBN 0-7134-5655-8)
In 1991, an American English edition titled My System: 21st Century Edition (ISBN 1-880673-85-1), edited by Lou Hays, was published by Hays Publishing. In this edition, descriptive notation has been changed to algebraic notation and many diagrams have been added.
In 2007, a British edition titled My System, translated by Ian Adams, published by Quality Chess (ISBN 91-976005-3-9) "This edition uses a brand-new translation that recreates the author's original intentions. For the first time an English-speaking audience can appreciate the true nature of this famous chess book."
Omitted was the Tartan edition of the 60's, Reinfeld editor of Nimzovitch's books.
Before going to My System, and the two other books by Nimzovitch,
(Chess Praxis and Blockade), read Aaron Nimzovitsch A Reappraisal by
Raymond Keene. I believe Keene revised the work.
An older work by Reinfeld is also available on Nimzovitch on 50 of his games. Reinfeld provided light but interesting notes.

As to the answer to the question on doubled pawns, there is probably no answer. Each game is different. What works in one game may not work in another game. Note that Fischer chewed up a player who had quadruple pawns. Botvinnik playing the White side of the French against the Winawer
in some variations played with doubled pawns.
In the Nimzovitch Indian variation, 1.d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. a6 B:N
and White has doubled pawns. Some players went after the lead c pawn as it was weak. Which is why in some games Petrosian played the strange 3.a3 and Spassky played often with the variation above (Samisch variation) 4. Bg5.

Alright, I'll give you my quick opinion of doubled pawns:

- They're good when they open key files for your use.

- They're good to control key squares (for example if you have pawns on c3 and c4, you've got d5 and d4 solidly under control).

- They're good to break up other pawns, such as in the Svesnikov, where you push f6-f5 and then f7-f5 to break up white's center.

- They're not good when they're restrained and easy to target. If they're backward or isolated they're especially weak.

- They can be bad when they block in your own pieces or take away key squares from your own pieces. Think of the typical e5-e6 advance where black plays fxe6 and that pawn just gets in the way and inhibits his development.

- Doubled pawns can almost be like being down a pawn when you have a doubled pawn in your majority. For example, look at the Ruy Lopez exchange where black can't really create a passed pawn with a7, b7, c7, c6 vs. a2, b2, c2.

Obviously this is just a quick view from the surface...each position is different and you'll have to evaluate it, but these are things to keep in mind.

As I do not own My System, and I am unfamiliar with the book, here's my understanding of doubled pawns.

Advantages:

a) Not all doubled pawns are weak.

b) Doubled pawns are useful in that they give the owner at least a half-open file to use for his/her rooks.

c) Doubled pawns are useful in that they can cover potential holes in an otherwise healthy pawn structure. If White has pawns on c3, c4, d3, and e4, Black does not have the option of putting a knight on d4, but if White's pawns were "healthy" on b2, c4, d3, and e4, then Black could take advantage and place a knight on d4 successfully.

d) Doubled pawns in the center increase control of important squares. In the Nimzo-Indian, White's pawns on c3, c4, d4, and e4 are a very strong center, and control b4, b5, c5, d5, e5, and f5.

Disadvantages:

e)Very hard to advance, especially the back pawn.

f) Both of the doubled pawns can be subject to attack. Again, in the Nimzo-Indian, the White pawn on c4 can be subject to attack by Nc6-a5, Ba6, or Qa4.

g) As Abba mentioned, a doubled pawn can prevent a pawn majority from creating a passed pawn, as in the Ruy Lopez Exchange.

h) Doubled pawns create some sort of isolated pawn or a pawn island.

i) Doubled pawns give the owner less options in terms of wing expansion. In the Nimzo-Indian, White is not able to expand on the queenside, since the isolated a-pawn is rarely able to create enough space.

j) If the front doubled pawn advances, but the rear one does not, then there will be weaknesses on the opposite color of the pawns, and a hole on the square that the front pawn previously occupied. Example: pawns on a3, b3, c2, and c3. If White plays c4, then the a4-d1 diagonal, the a1-h8 diagonal, and c3 will all be weakened.

That's about all I can think of. Good question, by the way.