Velikovsky set the chronological revisions published in the Ages in Chaos series
in the context of a cycle of catastrophes precipitated on Earth by cosmic events
in the Solar System.  He postulated that Venus was a recent arrival among the
planets, having been ejected from Jupiter during the 16th Century BC.  Traversing
the orbits of the inner planets as a comet-like object, Venus passed close to the
Earth on at least two occasions, disrupting our planet's orbit, axial tilt, and rotation,
and altering the lengths of the year and the day.  These changes brought about
the sequence of catastrophes recorded in the Bible as the Plagues of Egypt, and
the subsequent earthquakes and hails of fire attributed to the Biblical periods of
the Exodus, the Conquest, and the Judges.


Venus' careering path as it settled towards its current orbit also hurled Mars on a course from orbiting inside Earth's orbit round the Sun, to outside.  The close approaches to the Earth that Mars made during its progress caused a further series of disasters in the 8th and 7th Centuries BC.


Velikovsky provided a phenomenological (rather than historical) account of these events in his first book, Worlds in Collision (Macmillan, 1950).   In the opening sentence of his Preface, he described the book as "a book of wars in the celestial sphere that took place in historical times.  In these wars the planet earth participated too."  He supported this scenario by appeals to ancient history and to comparative mythology. not only from the ancient Near East, but from all around the world.  In doing so, he cited many source documents in footnotes.

This Internet site is particularly concerned with the sources he used in his historical reconstruction in the Ages in Chaos series, and particularly with the uses he made of them.  However, it should also be of interest to learn how he used his sources in Worlds in Collision.  An English mathematician, Bob Forrest, performed extensive research on the matter in the 1970s, self-publishing the results in a six-volume series (with an index in a seventh volume) under the title, Velikovsky's Sources.  The full work is long out of print; however, Forrest also published a one-volume condensation, A Guide to Velikovsky's Sources  (Stonehenge Viewpoint, 1987; originally published in the Stonehenge Viewpoint  journal, 1985).  I am pleased to be able to offer the latter at last as a complete pdf e-book, with the kind permission of Forrest himself and his publishers, Joan and Annette Cyr (in proxy for the late Donald Cyr).  Forrest has provided written permission for fair quotation from the Guide for academic non-commercial purposes, provided due credit is given.