Fascinating book. I read it (slowly and non-exclusively) from cover to cover, and I learned a lot about faux amis and also a lot about French institutional traditions (which explained a lot about EU institutions too, since they seem to be modelled more or less wholesale on their French counterparts).
While a lot of what they say is, as far as I know (which varies), still valid, it was also quite interesting to see that there has been a lot of slippage in both directions in the 35 years since this was published, such that quite a few items listed as faux amis no longer are - meanings have crossed languages both ways. Typically, I failed to note down any examples of this - sorry! It is likely to apply especially to institutional and business language, two of the ten themes covered here. Rest assured, there are more 'fun' themes too: food, travel, sex, clothes etc., for all you fun fiends out there.
Although there is some humour in the entries - quite a bit in fact - it isn't swamped in gratuitous facetiousness in the current fashion, so that's a welcome aspect of its datedness. It's never heavier or drier than it needs to be to convey the information it has to offer, but jokiness is never at the expense of utility either.
It also contains a concise but useful-looking reading list.
Recommended to anyone with an interest in the subject, be it amateur, professional or both.