Prompted  by an excellent post by 
Sheila on adult colouring books and a discovery among my books while unpacking , I'm sharing what you could say is my first attempt at an 'altered book'. 
 The discovery  was this copy of  
'Memoirs of a London Doll' still with my mum's notes attached from when she gave talks on toymaking ( she did City and Guilds in this as well as embroidery, I still have some of her innovative examples) . Although published in 1840, this was  an ex library copy published in 1926 and withdrawn from use at Darwen library in 1943 ( which is probably when my mum acquired it )
 As a child , besides playing at shops, I used to have a pretend library  of my own books where I'd write in the date at the front when it was due back just like the one which I was introduced to as soon as I could read ( so sad to see it's under 
threat of closure) 
 But probably before I could write, I'd coloured in some of the plates with  wax crayons, and it's interesting to see the progression in skill. I'm guessing that I'd got bored  and finished the colouring books I'd been provided with and wanted something more challenging! The quality of the paper was much better too.  'Magic' colouring books that you wet to reveal the colours were always deeply disappointing. 
This first one I was obviously trying out all the different colours in the crayon pack with mixed success - I've never been very good at( or motivated) to stay within the lines. Note the  early attempts at  colour mixing at the side! 
The second plate  I attempted (at the top of this post ) is much neater with a more restricted palette ( and a squiggle of green felt tip - rejected for further use) 
By the 3rd plate (below) I'd gone for a lighter touch with the crayons, 
 At that point I'd had enough of colouring in others works and did my own artwork at the back of the book - a patterned tent?  with a nice bit of frottage rubbing crayon over the tapes of the binding!
I don't remember being told off for colouring in this book  ( I probably thought it needed improving as my other books had colour pictures in !) but I remember  art materials and paper  always  being available.
The main reason I'm not interested in adult colouring books ( besides liking to draw my own designs) is that I don't like being constrained by the lines. At school in art classes I used to feel I wasn't painting 'properly' as my style even then was very scribbly and loose, enjoying colour mixing and making marks when everyone else was patiently and neatly going up to the lines with the colours provided.  Luckily good teachers encouraged me  and I didn't  succumb to peer pressure.