Schizotypal personality research holds the promise of critically important insights into the etiology and ultimate prevention of schizophrenia. This article provides a critical overview of diagnostic, developmental, demographic, psychosocial, genetic, neurodevelopmental, psychophysiological, neurochemical, neurocognitive, brain imaging, and prevention-treatment issues pertaining to this personality disorder. It is argued that genetic and early environmental influences act in concert to alter brain structure/function throughout development, resulting in disturbances to basic cognitive and affective processes that give rise to three building blocks of schizotypy-cognitive-perceptual, interpersonal, and disorganized features. Two clinical subtypes are hypothesized: (a) neurodevelopmental schizotypy, which has its roots in genetic, prenatal, and early postnatal factors, is relatively stable, has genetic affinity to schizophrenia, and may benefit preferentially from pharmacological intervention, and (b) pseudoschizotypy, which is unrelated to schizophrenia, has its roots in psychosocial adversity, shows greater symptom fluctuations, and may be more responsive to psychosocial intervention.