Dragonfly Field Guides
Until Theischingers seminal Complete Field Guide to Dragonflies of Australia came out in 2006, there wasn't any published and comprehensive information about Australian dragonflies.
There are a few guides of varying degrees of rarity - for Victoria, Dragonflies of Victoria (Theischinger & Hawking, 2003) is useful but out of print and hard to get hold of. There was Tasmanian Odonata published by Allbrook in 1979 but that's almost impossible to obtain now. There are a few copies of The Australian Dragonflies: A Guide to the Identification, Distributions and Habitats of Australian Odonata (Watson, Theischinger & Abbey) but it's far from comprehensive. It's a nice book (though difficult to obtain) from a natural history perspective.
The latest Complete Field Guide to Dragonflies of Australia, published by CSIRO, is less a 'field guide' and more of a 'guide' to dragonflies. There's no doub, it's the valuable reference resource for the group. If you haven't got it, buy it now. However, entomology often dictates that insects are identified by examination and this can mean netting and in some cases, killing and preserving for viewing under a microscope. The book is somewhat written in this tradition.
The guide goes so far to enabling field identification but the images in the book are really too small for reference and often only show one or other of the sexes. In many cases, there are hand drawn aids to focussing on certain body parts, but unless you know in advance exactly which bit to study, you might come home without the necessary evidence to identify your critter.
Fact is, unless you are intending to find a new species of dragonfly, most can be identified through binoculars. What we lack is a good database of images and in many cases, we know little about distribution and abundance. For instance, one of the few conservation-dependent and legally protected species (Ancient Greenling) was known finally from only one site until, following a concerted effort by Reiner Richter, its distribution was extended and numerous additional sites found. In Victoria, there are several species that are still known by only one site and new species being added to the state list every year.
So if you're looking for a field guide, you could do little better than the Complete Field Guide to Dragonflies of Australia but to extend the knowledge we already have of identifying dragonflies in the field and to stand a chance of identifying them, it's best used in combination with the Australian Dragonflies website.