Puzzle of the week #112

Level: 
4-Rook
Chess Diagram: 

[Event "Puzzle #112"][Date "2010.04.09"][Result "1-0"][SetUp "1"][FEN "8/2p5/8/8/5P1k/p7/7P/2K5 w - - 0 1"]

In the past little while we had to deal with 6 complicated middle game puzzles, so it is time to switch our attention to another basic endgame for a change. We already know the importance of passed pawns in King and pawns endgames and here we have no less than 4 such pawns on the board. There is a very nice method of play you need to remember in order to find the solution, method we have done at the club. Actually the admission test to level 5 has a puzzle where this method is being used. Without further ado here are your tasks for the week:
a) White to move and win
b) explain your solution

Total available points for this puzzle is 20. The answers will be published next week together with puzzle #113.

Puzzle #111 solution:
This was not an easy puzzle. It has remained in history as a very good practice material after the game Smyslov - Hort, Interzonal, Petropolis, Brazil 1973. I really appreciated your work analysing the position and most of you have written down quite a few good things. Of course writing your ideas could be improved, but in general you guys should be proud of your work. It is for the second week in a row when Owen has the most complete response; congratulations! Please read Canadian GM Kevin Spraggett's analysis below and compare it with your answer:

[Event "Puzzle #111"][Date "2010.04.02"][Result "1-0"][SetUp "1"][FEN "2r1rbk1/1bq2ppp/pp1p4/4n1P1/Pn1BP1N1/2N3Q1/1PP2RBP/3R2K1 w - - 0 26"]26.Rdf1 {Instead, he walks into a ferocious attack} 26...Re7? ({Now Hort must exchange Knights with} 26...Nxg4 27.Qxg4 Re7) 27.Bxe5 dxe5 28.Nf6+ Kh8 ({Clearly Black can not play} 28...gxf6 29.gxf6+ Kh8 30.fxe7 {and White wins as he pleases}) 29.Nxh7 {Ouch! That damn Knight is so annoying... Black is busted} 29...Re6 {Best is to resign, but nobody likes to resign in less than 30 moves} (29...Kxh7 {White breaks through with} 30.g6+ fxg6 31.Rxf8 {with mating threats}) (29...Rd7 30.Nxf8 Rxf8 31.Qh4+ Kg8 32.g6 {with a mating attack}) 30.Rxf7 {Hort continues for the spectators} 30...Bc5+ 31.Kh1 Re7 32.Rf8+ {It is forced mate.  Hort has had enough! Give that King Knight a cigar(!) for a job well done}

Correct solutions:
Owen - 25 points
Andy Y, Edwin, Karl - 20 points
Jeffrey, Andy Q, Nathaniel, Humphrey - 15 points
James - 10 points

Standings:
Owen - 234 points
Karl - 220 points
Andy Y - 218 points
Andy Q - 214 points
Humphrey - 175 points
Edwin - 172 points
Alex - 158 points
Jeffrey - 133 points
James - 128 points
Amir - 103 points
Nathaniel - 100 points
Rick, Marko - 10 points

Comment: 

What is the method?