Shimon started collecting fungi when he still lived in Israel and he even managed to end up in hospital having tasted a very small poisonous toadstool (read How I discovered mushrooms and mycology, and an article he wrote for Maariv in Mushroom Writings) [H]. However, he only became seriously involved in mycology in London when he joined the British Mycological Society (read tribute by Bruce Ing, a one time secretary of the BMS, in the memorial evening for Shimon - link opens as a PDF in a new window) about his involvement in the BMS. Regular walks in the woods, the collecting and identification of mushrooms, peering down the microscope and studying mycology books became a way of life for him, and he managed to infect many of his friends with his passion (see the photos in Collecting with Shimon).
In 1991 he joined a mycological expedition to the Siberian tundra - see his pictures of the tundra in Watercolour, and read about the expedition in two articles he wrote for Ma'ariv (Mushroom Writings 2 and 3) [H]. As with everything he approached, he did it thoroughly, with ambition and with obsessive precision. He designed two identification algorithms for two complex and controversial genera, inocybe and cortinarius, for professionals, and an identification key for amateurs, illustrated with his own watercolours (see Mushroom Drawings).