Unfortunately we don’t have many books that cover this topic. Here are some websites which may help.
British Nutrition Foundation – a useful short article about additives explaining their use and different types
Food Standards Agency – scroll down to the bottom of the page to find more useful links
Understanding food additives – a useful website covering all aspects of additives and preservatives
Wikipedia – contains lots of further links for more detailed information
Food reactions – although this website is biased towards the likelihood of allergic reactions, there is useful information about the different groups of E-numbers. Use the links on the top left of the page to find out more.