The Principles of Psychology is a monumental text in the history of psychology, written by William James and published in 1890.
There were four methods in James' psychology: analysis (i.e. the logical criticism of precursor and contemporary views of the mind), introspection (i.e. the psychologist's study of his own states of mind), experiment (e.g. in hypnosis or neurology), and comparison (the use of statistical means to distinguish norms from anomalies).
Read more about Principles Of Psychology: Analytical Arguments of The Principles, Nineteenth Century Experimental Results, Consequences of Comparisons, Publication Data