Beyond Capricorn
 The title of the book refers to the sixteenth century Dieppe maps of France which in part show land in a continent extending south of the Tropic of Capricorn, that is in the area of Australia. Trickett claims that the Portuguese were the first Europeans to discover Australia, between 1519 – 23, well before the first recognised landfall of Europeans in Australia in 1606 by Willem Janszoon. According to Trickett, the first European to sight Australia may have been Diogo Pacheco, a relative of Duarte Pacheco, at Napier Broome Bay in the Kimberleys in north-western Australia in 1520. Using an account from the history of the Portuguese empire in Asia by João de Barros, Décadas da Ásia, Trickett argues Pacheco was killed there in a battle with Aborigines while searching for gold. Trickett claims the Carronade Island cannons, originate from this voyage. Most of the book, however, focuses on the claimed voyage of a fleet of four ships commanded by Cristóvão de Mendonça, along the eastern and southern coasts of Australia then to New Zealand shortly afterwards, and another Portuguese voyage along the west coast. Trickett uses one of the Dieppe maps in the highly decorated "Vallard" atlas of 1547 to demonstrate this. Trickett claims that Mendonça sailed down the east coast of Australia, sailing into Botany Bay, and then around Wilsons Promontory to Kangaroo Island, before returning to Portuguese controlled Malacca via the North Island of New Zealand. He also claims the Portuguese charted the Western Australian coast, as far south as the south west tip of Australia. Trickett claims that the French Vallard maps were composed of several portolan charts that were incorrectly assembled from now lost Portuguese charts. Trickett adjusts parts of the Vallard maps by rotating them 90 degrees, giving what he claims is a remarkably accurate depiction of Australia's eastern, southern and western coasts Trickett goes through almost every written location on the Vallard maps, giving an English translation and explaining where he believes the place is located. He also mentions the mythical Mahogany Ship, the ruins at Bittangabee Bay on the south coast of New South Wales, various Aboriginal legends and alleged linguistic similarities, and various artefacts found in Queensland and New Zealand which he claims pre-date known European exploration, as further evidence of a Portuguese discovery of Australia and New Zealand.