[1][2] He is often grouped with Bruno Taut, Ernst May and Walter Gropius as being among the most significant representatives of the Modernist ("Neues Bauen") architecture that became important initially during the Weimar period, notably in respect of residential accommodation.

For detached buildings, such as the school (originally drawn by Haesler in 1911, and today used as a day centre and meeting space), in the village of Bannetze, he had invoked a more traditional repertoire, specifying an interrupted-hipped roof (Krüppelwalmdach).

Haesler championed the building of social housing, providing improved living conditions for an increased number of tenants at an affordable rent.

He wanted to reduce costs and at the same time improve living spaces by using standardised floor plans and employing the newly available steel frame construction methods.

With his first, the "Italian Garden Settlement" ("Siedlung Italienischer Garten") of 1924/25 Haesler incorporated inspiration he had gained from a visit to Bruno Taut in Magdeburg.

[5] Haesler publicised the modern design-language of the new buildings across Germany: shortly after completion, the Italian Garden Settlement came to be seen as the first "Neues Bauen" residential development in the country.

[5] An unusual feature of this development was that each residential unit was assigned its own tenants' garden, directly accessible at the ground floor level.

So far not mentioned works include: Otto Haesler was a member of the "Bright Star Masonic Lodge" ("...zum hellleuchtenden Stern") from 1909 till 1931.

Following the General election of November 1932, in which the Nazis, with 37% of the vote, emerged as the largest single party, they took power in January 1933, and the ensuing months saw a rapid retreat from democracy, in favour of one-party government.

[1] Violently attacked by the regime, in 1934 Haesler went into a form of internal exile, closing down his office in Celle and relocating to Eutin,[1][2] a small town in Schleswig-Holstein, some 130 km (80 miles) from the Danish border.

The eastern part of Germany was now subsumed into Poland and the Soviet Union, while the rest of the country was divided into four military occupation zones.

This involved a rigorously applied change of direction in favour of "National building", which meant a stigmatising of the Bauhaus movement and its economically focused functionalism.