Miriam Rothschild was the eldest of four children of Charles Rothschild, of the wealthy Anglo-Jewish banking family, and his wife Rozsika Edle von Wertheimstein, a Hungarian baroness. Her father was a pioneering naturalist and entomologist who, in 1901, discovered and named the flea that served as the main vector for the bubonic plague. She was born and raised on the family estate at Ashton Wold, near Peterborough, where she collected and studied the plants, insects, and animals. She was educated at home and then studied zoology at the Chelsea Polytechnic, now part of King's College London. In the 1930s, she established her reputation as a naturalist working at the Marine Biological Station in Plymouth. During World War II, she worked at the secret decoding facility at Bletchley Park. In 1943, she married George Lanyi, a Hungarian who changed his name to Lane, and had six children before divorcing in 1957. She became a renowned authority on insects, especially the flea. From 1968 to 1973, she was a visiting professor of biology at the Royal Free Hospital, Hampstead. She produced more than 300 scientific papers and books on subjects ranging from Fleas, Flukes and Cuckoos: a Study of Bird Parasites (1953) and The Atlas of Insect Tissue (1985) to biographies such as Rothschild's Reserves: Time and Fragile Nature (1997) and Dear Lord Rothschild: Birds, Butterflies and History (1983). She was named a Fellow of the Royal Society and of St. Hugh's College, Oxford, and was made a Dame of the British Empire in 2000. She was vice-president of the Royal Society for Nature Conservation and the Royal Society of Wildlife Trusts, and a trustee of the Natural History Museum.