I think the late J.V. Noble's "A Beginner's Guide to Forth" does a good job introducing the language and touching on some metaprogramming features. Near the end he demonstrates a library which extends the language to support infix math expressions (a "FORTRAN") to make scientific computing more convenient.
https://www.taygeta.com/fsl/docs/551.jvn.fall01/primer.htm#c...