How a £20 present can cost £100s! I have that book and enjoyed reading it (as I'm into vintage stuff) and still enjoy dipping into it a few times a year for reference... but it led to the purchase of several old folding cameras, and some servicing fees to get the ones I really liked working perfectly again so I can enjoy using them. How things can snowball!
I think it's out of print now and only available second-hand, but if you are interested in old cameras then it would be a good read over the Christmas and New Year break, plus you'd have a fair few £ of the budget left for a set of lens cleaning pens and a rocket blower, or something like that as a 'stocking filler'. I seem to remember that there are two editions, one catering for old cameras in general (the one I have) and one about collecting old SLR cameras.