Joseph-August Tharrats, also known as Tha, published his first drawing when he was only fifteen years old in the fanzine Patufet. Later on, he became an inker for the series 'Mortadelo y Filemon'. In 1974, he joined the magazine TBO, the oldest Spanish comic magazine, where he made the western 'Historias de Fort-Baby'. In 1979, he started working for the magazine Primeras Noticias, which was led by his younger brother, T.P. Bigart. His brother also became his scenario-writer. The same year, Tha also contributed to the satirical magazine El Papus with 'Momentos'.
Since 1981, the publisher El Jueves has published several books of his work, such as 'Ciclos XXI', 'El Miércoles Mercado', 'Secta Juevàtica' and 'Nuevo Kamasutra'. Around that time, his work was also introduced in France, in Fluide Glacial. In 1982, he started the humorous 'Absurdus Delirium' series. He drew 'Historias Frías', written by Jorge Zentner, which was published in magazine Cimoc in 1984. While making 'Absurdus Delirium', Tha published his work in Rambla, Cairo, Titanic, Penthouse and La Oca.