If you are after a comprehensive book that outlines qualitative research I would highly recommend this. Detailed postgraduate level, although very understandable. Interesting case studies from many disciplines. The one I found most memorable was a study searching through people’s rubbish and this found that in America poorer people buy branded smaller packets whereas richer people buy non-branded larger packets.

book review
Exactly What to Say: The Magic Words for Influence and Impact by Phil M. Jones
Want to prepare yourself for almost any conversation to give yourself a fair advantage? Magic words are used to get attention, here are the secrets: