I'm inclined to agree with Henry, a book on the history of music is probably the most likely source without masses of reading to deal with what's really a simple subject. There is a book titled "The Form of Music" by William Cole: "A concise guide to musical structures of the tonal era. The text is illustrated with many music examples," says the blurb. Another one by Wallace Berry: "Form in music."
I can't recommend them as I haven't read them but perhaps there are reviews.
The problem is there's almost nothing complex about these forms: Sonata form: the various "subjects" (themes), bridge passages, development, recapitulation, coda, etc., and some of these books will contain copious examples when really, after sussing the first example, the "student" should be able to analyse a classical work themselves. Get the jargon under ones belt then apply it to (e.g.) Mozart's Sonata in C or Eine Kleine Nachtmusik; or Beethoven's Symphony No. 2. Of course there are exceptions but beyond finding out "how a composer did it" there's little point in analysing exceptions to get to a generalisation.
Forms like Sonata Form, Rondo etc., are quite well defined on the web. This may be enough.
As for composing beyond the classical, it's as long as it's broad. As Henry says you may be looking at individual composers or genres (e.g. the dodecaphonic era, Schönberg and Webern). Impressionism: Debussy.