Well it seems that we are overloaded with various kinds of ideas on how to improve our lives, so here is the rush to go buy new books he he. It's a form of spiritual consumerism.
My observation is that buy several books and absorb their contents, do the processes explained in these books, observe the results. If the results are better than average, then stick to the particular processes for a while and when you feel that you need to change your routine a bit, then you can look for another books on the same subject. If the results are not better than the average then these books you already have might not resonate with you within so the quest for new books begins again.