Herbert Otto Roth (7 December 1917 – 27 May 1994) was a notable New Zealand socialist, labourer, librarian and historian. He was born in Vienna, Austria in 1917. In his native Austria, he was known as "Otti", but in New Zealand, he was known as "Bert".
Roth was leader of the Red Falcons in Austria. He fled from his native country to avoid conscription after having sworn an allegiance to Adolf Hitler. He then lived in Grenoble, where he was later imprisoned as an enemy alien. His mother managed to organise a permit for him to emigrate to New Zealand, and he arrived in Wellington in April 1940. He immediately became politically active in left wing circles, but was forbidden by the Department of Justice to take on official positions, as he was classed as an enemy alien. Roth applied for naturalisation in 1944, and was granted citizenship in March 1946.
Roth joined the Air Force and this allowed him to study towards a Bachelor of Arts at Victoria University College. After attending the New Zealand Library School, he worked for the National Library Service in Wellington. He was later the president of the New Zealand Library Association. In January 1962, he started work for the University of Auckland Library. He went into retirement in 1983.
He married Margaret (Margot) Frances Hogben on 29 November 1946. She was a journalist, and the granddaughter of George Hogben. Roth's first book was a biography of the seismologist. After that, Roth has mostly written about labour history. His most important work is Trade unions in New Zealand past and present, which was published in 1973. He was a major collector of union and labour publications, and his collection is today a major resource for the Alexander Turnbull Library.
He died at his home in Mount Eden on 27 May 1994. He was survived by his divorced wife, two sons and a daughter.