Chess books about Alekhine Defence

Alekhine´s Defence, 1.e4 Nf6, is another opening which issues an immediate challenge to white´s e4-pawn. Black lures white's pawns forward in the hope of then proving them weak, but most players believe white is being given a bit too much space. The main lines start after 2.e5 Nd5 3.d4 d6. The Four Pawns Attack, 4.c4 Nb6 5.f4 is White's most ambitious approach, and demands specialist knowledge from both players. It remains very popular in correspondence chess, but the most common move for over-the-board players is the modest 4.Nf3, with which white aims to keep a pleasant spatial plus. In most lines he is able to do so, but the 1990s have witnessed some startling successes for black after 4...dxe5 5.Nxe5, both with the positional 5...g6 and with 5...Nd7, inviting the chaotic sacrifice 6.Nxf7.

from Nunn's Chess Openings.