I bought this book in preparation for my first visit to Australia so cannot comment on its accuracy in the field. However, having written a field guide myself [Mountain Flowers and Trees of Caucasia], I feel qualified to say something.
A field guide must fit the pocket or knapsack and be light enough to carry all day; Michael Braby's book does both. It has 340 pages, soft-back, measures 21 x 15 x 2 cm and weighs 700 grams. The paper is tough enough to stand reasonable wear.
There are 40 pages of preamble and introduction which clearly and thoroughly describe the life-cycle, basic anatomy, behaviour and distribution of Australian butterflies. The habitat photos are particularly useful for a new-comer to the continent. A check-list, glossary and indexes to common and scientific names complete the book.
The 270 pages of descriptions cover all species recorded from Australia. Text is on even-numbered pages (left hand side) and illustrations are opposite. This is particularly useful when the beginner hasn't a clue where to start (in spite of the introduction) and can flip through the pictures, praying for luck, inspiration or even recognition. There are mostly three species per spread.
Individual descriptions include clear, full-colour photos of male & female, upper and lower surfaces. Text pages have coloured common names (you would discover how useful this is when using a field guide that doesn't), distribution maps and flight seasons of northern and southern populations where appropriate. The text itself is clear and thorough.
All in all, this is a brilliant book.