The calendar recognises three types of astronomical year&colon; tropical year, sidereal year and anomalistic year. The anomalistic year is usually defined as the time between perihelion passages. His book "Christian Science, Medicine, and Occultism" (1902) is an early text on anomalistic psychology. Wiseman has published studies on anomalistic psychology and the psychology of paranormal belief. Jastrow was a leading figure in the field of anomalistic psychology. Hall was an early psychologist in the field of anomalistic psychology. His book is seen as an early text in the field of anomalistic psychology. This is called its "anomaly", and it repeats with its own period; the anomalistic month. A critic of paranormal claims, he was influential in the field of anomalistic psychology. The anomalistic month is the time between perigees and is about 27.55 days.