Sources & Where to Look (legal options)
GD&T is the most complex part of technical drawing. This classic workbook is often cited. Older editions (pre-1994) are sometimes available as instructor review copies in PDF format on university engineering portals. technical drawing books pdf link
Or search blogs like or "The Tools of the Trade" – they often write interesting historical articles and link to free PDFs of out-of-copyright manuals. Sources & Where to Look (legal options) GD&T
You're looking for a good resource on technical drawing, specifically in PDF format. Here are some popular and reliable sources that offer technical drawing books in PDF: technical drawing books pdf link