In this work Emms seems to favour the lines with the immediate recapture of the pawn: 1.e4 d5 2.exd5 Qxd5 3.Nf3 Qa5 - which is a perfectly respectable choice for black. The problem is this coverage takes up too much of the book, and not enough space is given to the possible gambit variation which goes 1.e4 d5 2.exd5 Nf6 - a line which I personally prefer, because of the element of surprise it gives OTB - in the recapture lines, even if white has never played against the Scandinavian in his life, he can get quite a combatable game just making obvious developing moves and kicking black's queen around.
The mainline with 2...Nf6 3.d4 is covered quite well, as are a couple of other white third move choices. However the lines where white tries to hang onto the pawn temporally or permanently with 3.c4 leave a lot to be desired - 2...Nf6 3.c4 c6 4. dxc6 Nxc6 (the full Scandinavian Gambit) amazingly isn't covered at all! Instead Emms assumes the game will transpose into a Panov-Botvinnik attack where white doesn't play 4. dxc6 and instead goes into an exiting line of the Caro Kann - coverage of this isn't very deep anyway (we are referred to another book!) but it seems strange to include this, but not the actual gambit - to me the P-B is a lot less within the scope of the work - admittedly it's a better option for white to transpose, but anyone under ECF: 130 say, isn't going to know that!
Believe me 3.c4 is a common response at club level, so this is a pretty big hole. There is an alternative given to playing 3...c6 which is 3...e6 - known as the Icelandic Gambit, but I've never felt that gets black much for the gambit pawn and the lack of central pawns will tell against him in the middle game if the initial attack fails - Emms admits as much in the book! You also feel it has been stuck in as an afterthought - the section is about 4 pages long, right at the back of the book.
All in all it's not bad, especially if your interested in playing 2...Qxd5 but I've had to order James Plaskett's book as well (which I'm told will fill in the gaps - I'll get back to you on that!) to cover my personal needs.
Every chapter has a theory section as well as a good volume of example games so you can get a nice feel for the positions which arise. It's just a shame about the limited scope in some lines.