Roberts’s three volume work bound into two, with the original page numbering and indexes. New addenda and corrigenda are appended to the first volume.

The first volume (parts 1 and 2) comprises the keys, descriptions and genitalia figures, and also includes a 16-page appendix of corrections, alterations and additions. These three parts are merely bound together, retaining separate page numbering and indexes which makes it quite confusing to use. The first half (the old part 1) comprises the introduction, key to families, and descriptions of species for families Atypidae through Theridiosomatidae. The second half (the old part 2) covers the money spiders (Linyphiidae).

The second volume (part 3) has 237 colour plates mostly depicting single specimens. The beautiful paintings are from fresh specimens in alcohol so the colours are not true to life, but this is how you see spiders when identifying them. The alcohol brings out the colour and pattern by reducing the obscuring effect of surface hairs and waxes.