The most useful photography book I have ever read is Alfred A. Blaker's Handbook for Scientific Photography (1977). Despite the fact that the book was written when photographers didn't even dream of digital photography, it is as useful as ever, because most of the book is about "general techniques" or rather, about various lighting methods and which to use depending on what type of object one is photographing. Among the specific objects discussed in the book are pinned insects, eggs, fossils, crystals, impressions, potted plants, leaves, coins, glass laboratory equipment and so on.
Some of Blaker's lighting techniques are elaborate set-ups, while others are exceedingly simple. An example of the latter is the use of a simple white card as a reflector to obtain more even lighting when the object being photographed is illuminated by a single light source.
Here is an example of the use of a reflector card to photograph a live snail. My light source was a flash (Olympus FL-36) attached to the camera (Olympus E-500 + 35 mm Zuiko) with a flexible cable and hand held from the right at a distance of about 25 cm away from the snail. The snail was crawling on a glass plate with a neutral gray card below it. The picture on the left was taken without a reflector card. Not surprisingly, the side of the snail's shell facing away from the flash didn't get enough light. The picture on the right was taken with a small piece of white card serving as a reflector behind the snail (arrow). Now the shell is more evenly illuminated.
The snail was a Triodopsis sp. that was the subject of this post and which I still haven't identified. The diameter of the snail's shell was 12.1 mm.