Professor Crystal's "The English Language" is a must-read for all language students and in general everyone interested in language. Professor is famous for his reader-friendly style. A quality which is especially beneficial to the historical section of the present book.
The discussion in the book starts with the major aspects of language - vocabulary, grammar, and pronunciation. And if language students should think they are familiar enough with these topics - they will, however, find many fascinating nuances and perspectives not encountered or thought about before.
The second part of the book discusses the uses of language such as its proneness to ludicity, idiolect, its different manifestations in different occupational groups, and the ripe effects of technology in the productive evolution of the English language. Professor is quite infecting in his fascination with the unlimited potential of the language.
The third section discusses the historical growth of English - in such an accurate, comprehensible and flexible manner that you are rather quick to grasp the historical situation, get a feel of the language at different periods in history and remember all the important dates through easily associated events.
This section includes a neat demonstration of the relation and differences between British English and American English.
The great merit of this part is also the discussion of Scots and Irish English alongside Australian, New Zealand, South African, Canadian Englishes.
And the introduction to the Plain English campaigns is another fresh topic which has found space in this remarkable book.
I strongly recommend it!