I used this book whilst in the library quite a few times and found it useful, as a student radiographer, for learning the very basics of different imaging modalities. It covers MRI and CT and so on in a brief way. I wouldn't say this is especially useful if you already have some knowledge of these modalities. There's a small amount of coverage, a chapter, on the production of x-rays and types produced but again this is quite brief.
If you're looking at this textbook because you're after an overview of a certain modality then I would recommend this as a great starting block. If however, you're looking to find out about x-ray production and essentially the physics behind imaging then I would recommend "The principles of radiological physics" which is simple to read and has more depth - this depth is essential in understanding and for revision/exams.
As I've mentioned, this is useful but again only as an overview. I personally would recommend investing in a more detailed book, not necessarily more complicated just with more depth. This way you'll only need that one book as opposed to purchasing this one and having to get another one once you've developed your understanding.