Manning's 1969 book is very out of date and much of the taxonomy has been changed. His 1995 book on the Stomatopods of Viet Nam featuring many of Serene's watercolors of stomatopods painted in the 1930's is a remarkable volume. I love the paintings and frequently use them in my seminars.
Crustaceans of the World by Helmut Debilius (not sure of the spelling) is fairly good and has photos of about 20 species. If you like crustaceans, it is worth getting and is available from IKAN Press.
By far the most authoritative book on stomatopods is Shane Ahyong's disseration on stomatopod in Australia published by the Australian Museum in I believe 1999. No color pictures, but if you want the latest higher taxon keys, this is the only book that has it.
Sorry I can't be more specific. I'm currently off the Great Barrier Reef chasing stomatopods and don't have my references with me.
Roy