German bass player, born April 12, 1952 in Ulm. Father of and .

and were together with Hattler in a group called the Progressive Jazz Group Ulm. All members were still in school and Hattler played contrabass in the band. Still at school in Ulm, Hattler was asked to co-found a Rock band called Inzest in 1968 together with siblings Jan Fride and , who studied in Berlin before. In 1969, Inzest considered to become a professional band and in 1970, the three musicians together with Johannes Pappert founded the first incarnation of .

After a short period in Berlin and a return to Ulm, Hattler had a dispute with the band, left and settled to Wintrup, near Paderborn, where he was invited by Progressive Rock band , a band from Schwäbisch Gmünd, Germany. The band lived at the farm in Wintrup as a community and the musicians invited the other musicians from Kraan, which led to a state, where the other Kraan members moved in, but at the same time, the band Erna Schmidt split and one after the other of their musicians left Wintrup. It turned out, that both bands were not much compatible to each other.

It was 1971 and Kraan reformed in Wintrup and Hattler was again part of the band, and in the rural area of Wintrup, they lived together in a community in this farm, which was built in the 5th century. In the following years, Hattler lived there with his band, producing their albums and using it as a homebase for their many live concerts. In 1975/1976, Hattler moves out of the farm, as his first child Max is about to be born. In 1975, Hattler also starts to support under his alias .

Hattler eventually moved back to Ulm, in 1977, Kraan split and Hattler recorded a solo album that year. Also, he was active as guest musician on some albums of his former bandmates. In 1978, Kraan reunited and this second incarnation of the band lasted until 1983, when Kraan split for the second time. Hattler then shortly played with the New Wave band .

In 1986, he met trumpeter , who also originated from Ulm and . From this collaboration, the Jazz Fusion duo was formed in 1991 in Ulm. Kraus and Hattler were the core of the duo, but were regularly supported by . The band became a genre-defining Fusion band, which abstained to employ drums in their music. The band continued until around 2012.

In 2000, Hattler managed two important steps in his career. First, he recreated Kraan a second time, mainly for live performances. Second, he founded his project , where he incorporates Electronic Music in his sound and cooperates with changing musicians, also from the next generation.

In 2001, Hattler also founded his own label , which is based in the small city of Senden near Ulm.