My personal opinion: 'Handling the Big Jets' - Number One for all the reasons statred above - plus it puts the theory of operating a heavy aircraft into reasonably plain English that pilots can understand without being patronising.
'Great Answers to Tough Interview Questions' by Martin John Yate is also a very useful book - not just because it does give some answers but also all the peripheral stuff about how to deal with phone interviews, what to wear, how to find jobs that aren't necessarily advertised etc. It is not in any way airline/pilot specific but as a general job-seeking book it is excellent.
'Preparing For Your Cathay Pacific Interview' by Captain XYZ is very good for general tech questions - and many different airlines apparantly use it as a basis for their tech questioning. It doesn't give you the answers to the questions but does get you looking for interesting operating aspects of heavy jets (particularly 747 and A340) and gives an excellent grounding for all sorts of interview questions.
'Ace The Technical Pilot Interview' by Gary Bristow is quite good, it gives answers to technical questions that can be a useful refreshing aid to interview questions and 6 monthly checks.
Apparantly you also need a personality, experience and the ability to drive a simulator, which is where I keep falling down at interviews!!
Hope this helps
LC