This book was set for a class, but was never really used. I've dipped into it now and again, but I haven't found it particularly useful, which is perhaps why we didn't use it. There are some exercises, but I didn't feel a burning urge to do them, they didn't inspire any immediate thoughts. There are some anecdotes, but I didn't relate to them all that well -- Julia Bell describing how a literature degree took away her hunger for books, for example, but while my degree has got in the way of my reading, to some extent, it hasn't taken away the love of it. (On the contrary, I love and adore digging into a book or books to construct an essay, and my degree opened up the world of reading and writing poetry in a way I'd thought I'd never really get.)
The strength and weakness of it is that it deals with a wide range of topics. It's very general. So if you're an absolute beginner, perhaps it's worth reading, but for deeper insights, not so much.
Actually, I can't think of many books on writing I've found genuinely useful in that way. Stephen Fry's The Ode Less Travelled made me write poetry enthusiastically, eagerly, yes, and Ursula Le Guin's Steering the Craft taught me about things I'd never thought about before, like thinking about the rhythm of my writing. I travel everywhere with those two books, just in case I feel the urge to turn to them again. And there are books which are fascinating because they're all about a personal view of writing, which works too. This one just ended up being none of those, really.