Royal Australasian Ornithologists Union early 20th century called themselves 'oologists', though the distinction between the notionally scientific discipline of oology and simple egg-collecting was blurred. Identification of any but the most common and distinctive species usually entailed the collection of specimens to be made into study skins. Modern field-guides did not exist and few people could afford the massive multi-volume, lavishly illustrated, handbooks of John Gould and Gregory Mathews. However, both Archibald J. Campbell and Alfred North had produced comprehensive guides to what was known about the nests and eggs of Australian birds, with illustrations of the eggs rather than of the birds themselves,
What Is Life love song – perhaps a "lovingly crafted paen" to Harrison's wife Pattie, as Alan Clayson puts it – or a devotional song like many of Harrison's compositions. Ian Inglis writes that the song title suggests a "philosophical debate about the meaning of life", yet its rendering as ""what is my life"" in the choruses "reshapes [the meaning] completely". Theologian Dale Allison finds no religious content in "What Is Life" but notes the "failure of words to express feelings" implied in the opening line (""What I feel, I can't say""), a recurring theme of Harrison's spiritual songs such as "That Is