For the serious student of slang, it is an essential dictionary.
The pièce de résistance of English slang studies.
Jonathon Green’s Green’s Dictionary of Slang is quite simply the best historical dictionary of English slang there is, ever has been or (in print at least) is ever likely to be.
Jonathon Green’s is a dictionary for the ages, as special a catalog of word-biographies as James Murray himself might have created, and likely to endure as long as the OED, to which it is a most wonderful appendix. To praise another way: Green’s dictionary is, in short, the dog’s bollocks.
This work is monumental in several senses. […] In its historical approach, GDoS matches the Oxford English Dictionary and it’s not hyperbolic to suggest that it’s the OED of slang.