My very elderly (better part of 30 years old) 21st Edition copy of Patons Woolcraft - still my 'go to' after all these years.  I did have an earlier edition, the 18th I think, but I wore it out (and shared it with my sister and mother).

I taught myself to knit from the Ladybird book on knitting - alas it seems my copy is long since lost, and I'm not about to pay £3.50 (or more) to replace it purely for nostalgic reasons.  My first successful knitting project was a bright green pencil case (with a white zip hand stitched into it - back in the 70s it was expected that you could put in a zip by age 11!) before I soon progressed to a jumper with a cable design up the front, and in time won prizes for my fairisle and Arran knits.

Now, I just dug out the book for fancy stitches to work into squares I'm knitting for a charity.  Just opening it, looking at patterns that have been knitted over the years is a source of great joy... and I realise now that I was actually a mighty good knitter back in the day!