Synoptic Gospels texts of the three synoptic gospels often agree very closely in wording and order, both in quotations and in narration. Most scholars ascribe this to "documentary dependence", direct or indirect, meaning the close agreements among synoptic gospels are due to one gospel's drawing from the text of another, or from some written source that another gospel also drew from. The synoptic problem hinges on several interrelated points of controversy: Furthermore, some theories try to explain the relation of the synoptic gospels to John; to non-canonical gospels such as Thomas, Peter, and Egerton; to the Didache; and to lost documents such
What Bird is That? according to their usual habitat. The accompanying text included brief notes on distribution, breeding and behaviour. While initial sales were poor, history tells us that Cayley had accurately discerned a market need and successfully responded to it. During WWII sales accelerated and Cayley’s first collection, reprinted time and time again, eventually became a household name among birdwatchers and the book was recognised as an Australian classic. The original sponsorship of "What Bird is That?" proved a great investment for the Gould League, who benefited from the sale of its numerous reprints and revised editions. By 1960, it was rated the