If you want to do some realistic IELTS reading practice, the only books that I recommend are Cambridge IELTS books and the two 'Official Practice Materials' books.
Here are some problems that I've seen in other 'unofficial' books:
- Tests can be too easy or too difficult.
- Topics may be covered that would never appear in a real test. For example, a passage about the politics of a particular country would not be used in a real test.
- The answers in the passage might not be in order. In real tests, answers to most question types are almost always in order.
- Questions are badly written and confusing.
You can still use unofficial books for reading practice. Just don't expect the tests in them to be realistic.