A good book, fitting the format of the Crowood series, with the usual expected quality and loads of detailed pictures. The detail history per individual aircraft in the main body of the book is not something I appreciate, and the fact the author is not consistent and sometimes details in groups aircraft but then sometimes reverts to individual aircraft histories causes a bit of frustration - this material would be much better as an appendix and the general points of interest should appear as a collective history narative for the S1, S2 and RAF S2 aircraft groupings. Due to this it can feel like the author is padding our the book, but apart from this the content is good and easy to read. Value is average if you have to pay full RRP, but if you can get this at a discount it is a good book to have on what is a classic aircraft.