He wrote several books on nature in the Maltese Islands, such as Know the Trees and Know the Birds.
He also discovered a sub-species of moth which has been named after him - Pterolonche vallettae.
[citation needed] His collection of butterflies and insects was the largest in Malta.
[1] He was one of the first people in Malta to start a public consciousness to protect the island's environmental heritage.
He was a headteacher at three state schools, in Luqa, Għaxaq and Birkirkara and later an inspector of government schools[2] for the Department of Education.