Perhaps Marin will recommend 1.c4 Nf6 2.Nf3 e6/c6 3.b3 d5 4.e3, which if I recall correctly has been quite a fashionable system of late in the past 5 years. White can also play using a double fianchetto, although I have never considered this to be overly dangerous for Black.

After 1...e6/c6, 2.Nf3 d5 3.b3 is quite similar. Most of the time Black eventually plays ...Nf6 to transpose to the 1...Nf6 lines above. 

Alternatively it is possible that Marin will refer readers to Avrukh's or Schandorff's book, although since the book is meant to offer a 'complete repertoire', I highly doubt that Marin will do this. 

I also wonder whether what Marin will recommend against 1.c4 c5 2.Nf3 Nc6: 3.Nc3, 3.d4 or 3.g3, all of which are highly popular for White. 3.Nc3 and 3.g3 can also transpose into each other in several instances, e.g. 3.g3 e6 4.Nc3 or 3.Nc3 e6 4.g3 to mention a simple example.

According to the Dossier for Mihail Marin on Big Database 2008, the following variations are his basic English Opening variations as White:

1.c4 Nf6 2.Nf3 g6 3.g3 Bg7 4.Bg2 0-0  74%, 2587 25 Games 
1.c4 Nf6 2.Nf3 e6 3.g3  76%, 2627 21 Games 
1.c4 Nf6 2.Nf3 c5 3.Nc3  68%, 2575 19 Games  
1.c4 Nf6 2.Nc3 e5 3.Nf3 Nc6 4.g3  66%, 2573 31 Games 
1.c4 e5 2.g3  69%, 2602 26 Games  
1.c4 e6 2.Nf3 d5 3.d4  64%, 2542 28 Games  
1.c4 e6 2.g3  75%, 2629 18 Games  
1.c4 c5 2.Nf3 Nc6  69%, 2604 21 Games 
1.c4 c6 2.e4 d5 3.exd5 cxd5  65%, 2553 17 Games 
1.c4 g6 2.Nf3 Bg7 3.d4 Nf6 4.g3 0-0  60%, 2578 21 Games 

It looks like Marin will recommend 2.Nf3 against the majority of moves, but it will be interesting to see whether Marin recommends 2.g3 or 2.Nc3 Nf6 3.Nf3 Nc6 4.g3. Having a quick look at the database reveals that after 4.g3 d5 5.cd5 Nd5 6.Bg2 Nb6 he prefers the variation 7.0-0 Be7 8.a3 0-0 9.b4 Be6 and now 10.Rb1 instead of the more common 10.d3. I wonder if Marin will recommend this in the book or choose a slightly different line.

Does anyone know when 'Grandmaster Repertoire: 1.c4' by GM Mihail Marin is due to be released? According to one site I found, the book is due for release in 4 months time from now, although there is no guarantee that this is correct.

What repertoire and recommendations do you think Marin will offer in the book?