Perhosmaailma, 2025.  by Helmut Diekmann, Reima Flyktman, Heikki Tabell, Helmut Diekmann, Matti Selänne, Olli Pihlajamaa, Teppo Salmela. ISBN  9789523739611 Published by Readme.fi, Helsinki, Finland. 528pp

(Note: Perhos comes from the word perhonen, which means “insect of the order Lepidoptera; butterfly, moth or skipper.”)

 Classification was invented by man to make it much easier to talk about the huge biodiversity on earth, however some countries’ languages do not distinguish the popular demarcation of butterflies from moths.  Certainly the natural world knows no precise boundary; such is the intimacy of evolution.  This Perhosmaailma book (Butterfly World) is roughly 50% butterflies (mostly all species in Finland) and 50% moths (a tiny fraction of moth biodiversity in Finland). The book is heavy (1.5kg) so moths make 0.75kg, so a big deal.  But all the book is fantastic to a butterfly-lover such as myself who has published lots of books on butterflies of Europe, N. America and the world.  The species shown appear to be well described, certainly exceedingly well illustrated. It is a joy to read, and to explore the Finnish countryside through the butterflies. These butterflies give a sense of place to Finland for this contribution to biodiversity. The book is entirely in Finnish so I am rather stuck with checking all the text. Each of the butterfly species are illustrated as full page spectacular images, usually in habitat, so you get a feel of the Finnish forests, the pines, the meadows, the mountains, the wetlands, bogs and the wildflowers, since butterflies have diversified successfully into all habitats.   When the book is shut, there are coloured bars on the edge indicating where the ‘blues’ are, green for the ‘whites’, reds for the nymphalids and greys for ‘moths’ (always the apparent less glamorous relations). It would have been useful to have maps showing distribution of each species, but with the butterflies males and females are shown, and sometimes caterpillars.  A good range of moths have been illustrated, not going to full page, but still showing their bright colours, especially in some of the day-flying moths (someday-flying moths are brighter than butterflies). It was interesting to see the good range of hawk-moths shown, since many are migrants from Africa that go north to enjoy the diversity of wildflowers that emerge in the continental summer, that on some days can be hotter than the Riviera, and, with longer sunny days have more time to sunbathe.  Underwings, tigers, zygaenids, bee mimics are all included. It is fascinating to see the grayling relations typically sun-bathing sideways on rocks – of which Finland has many.  As so much of Finland is forest of course the timber-devouring caterpillars of the leopard moth, pine hawk-moth, poplar, lime and aspen-dependent moths are shown. Overall, this is a superb book on the butterflies of Finland and a good range of their moth relatives. There are references, links to further information and an index only to Finnish names of the insects.