The responses you've received seem to reflect some confusion regarding your ultimate objective. Is your interest primarily academic (i.e., in psychology for its own sake) or practical (i.e., to develop the skills essential for the effective performance of mentalism)? Although an understanding of psychology is important for both, the suggested course of study for each of those would IMO be significantly different. If your primary interest is in mentalism, which is what I surmise from you question, I think most of the "workers" in that field would recommend Corinda's "Thirteen Steps To Mentalism" and Annemann's "Practical Mental Effects," although both are quite dated (1940s for Annemann and 1960s for Corinda), as the essential "primers" in that field and that they should be carefully studied as a prelude to tackling the more contemporary works on the genre.
In addition to Annemann, Corinda and the more current writers on mentalism, I have found that a study of psychology in general (i.e., unrelated to the performance of mentalism), with emphasis on the psychology of cognition and perception and how it makes truly rational thought almost impossible as a result of the inherent biases acquired in the course of human evolution, is also invaluable.
If you contact me at my primary e-mail address (firstname.lastname@example.org
) I will be happy to provide a bibliography of suggested reference material.