This new edition of R. A. Hudson's Sociolinguistics will be welcomed by students and teachers alike. To reflect changes in the field since publication of the first edition in 1980, the author has added new sections on politeness, accommodation, and prototypes; and he has expanded discussion of sex differences in language use, and the relationship between language and thought. Ample coverage of classic topics such as varieties of language, speech as social interaction, the quantitative study of speech, and linguistic and social inequality, remains.
This is not a new book and you notice it in many places. For example, when discourse structure is discussed (or left undiscussed) or in the chapter on quantitative study of speech which definitely needs a serious update. The book also seems a bit unfocused to me as it introduces many interesting topics but does not cover them in enough detail. For example, you'd better read about prototypes somewhere else (e.g., "Linguistic Categorization" by Taylor).
The book is pretty solid as an introduction. I particularly liked the chapter on linguistic inequality — something that I haven't seen in such texts (not discussed at such length anyway).
The book would have benefited from control questions after each chapter (it's an introduction after all), though. Also, most of the pictures are ill-made and quite hard to follow, even with the explanations in the text.