Stored behind the metre-thick walls of Vaduz Castle lay a priceless manuscript - the fourteen volume Liber Regni Vegetabilis (Book of the Plant Kingdom). This work, created in the 18th century, and quite unknown until now, contains naturalistic illustrations of some 3,100 different plant species from all over the world, depicted in captivating beauty and exceptional detail. This is truly a work of superlatives: for more than 30 years several highly qualified specialists worked together to capture in art the native plants of Lower Austria and Moravia, the cultivated plants of field and garden, and above all the short-lived flowering splendour of the greenhouses of Vienna and surrounding region. More than half of the watercolour paintings is the work of the brothers Franz and Ferdinand Bauer, who are amongst the most famous botanical illustrators of all time. Indeed, Ferdinand Bauer has been described, with justification, as the `Leonardo of natural history illustration'. We can appreciate how the Bauer brothers used codes to specify the colours to illustrate the plants, and with what refinement they produced their watercolour paintings. Also documented is the dramatic rescue of the Codex Liechtenstein during the Second World War, involving its being transported from Vienna to Vaduz. What remains is a work of outstanding quality, truly A Garden for Eternity.