Looks like Bookman. The closest digital versions I could find are Bookman Headline and Bookman Old Style.

- Lex

I originally read your title as “Heading from 1930s German textbook”. If it’s from 1930, the font is probably Antique Old Style, the precursor to Bookman.

- Lex

Thanks Lex. It does indeed look like Antique No. 7 old style. I feel a bit silly now, especially as I have a reprint of a Miller & Richard specimen book sitting on my desk.