I am lucky as I share an allotment with an old hand. He has however welcomed the varieties I have grown on the plot as they are not what he would normally grow.
I would recommend 3 books:- Joy Larkcom – Grow Your Own Vegetables (deemed to be the bible amongst growers), Alan Buckingham - Allotment Month by Month (A DK book so loads of pictures and easy to read whilst being helpful) and Lia Leendertz – The Half Hour Allotment (Good as it suggests how many plants to grow).
We are fortunate in that we have a polytunnel and for that I would recommend Gatter & McKee – How to grow food in your polytunnel all year round (good because they are British so you know they are growing things for our weather. Some American books appear good but are written for warmer areas than the UK so not much help)