What font type was used in book found on post in stackoverflow?

Question

I need identify this font (or similar) (please only free-fonts, google fonts will be preciated). Similar fonts will be also upvoted because really helps me too.

Thanks in advance.

Answer 1

The font is Computer Modern (Wikipedia), an original design of Donald E. Knuth for use with his TeX typesetting system. It's the default font in every TeX environment set-up, and it has an extensive set of matching Math symbols, so it's still being used extensively in scientific publications.

It is classified as a modern Didone:

• Straight (hairline) serifs without brackets.
• Vertical orientation of weight axes. (The vertical parts of letters are thick.)
• Strong contrast between thick and thin lines. (Horizontal parts of letters are thin in comparison to the vertical parts.)
• An unornamented, "modern" appearance. (http://en.wikipedia.org/wiki/Didone_(typography))

The original fonts were scaled to the required size with a unique system that allowed independent horizontal and vertical calculation of the stems, and then saved as bitmaps for use on that scale only. As such, it's hard to mimic the original technology with the modern 'linear' scaling technology that Postscript and TrueType offers -- some font packs offer different font files to use in different sizes.

Sample image:

Answer 2

It appears to be Century Schoobook, although the numerals seem a tiny bit "bolder" than the roman. It's definitely in the Century family. https://www.myfonts.com/fonts/bitstream/century-schoolbook/