The first part of this book gives invaluable and in-depth advice about how to bake for people with food allergies and intolerances, including how to avoid cross-contamination, hidden ingredients and which are suitable for each type of diet. Unlike the previous reviewer, I don't think the book claims to cover all bases in one. I never for one second thought that I'd find recipes that were gluten-free AND nut-free AND egg-free AND dairy-free. I think that is almost impossible to achieve and I certainly wouldn't mark the author down for this. As a vegan, I know I can adapt a dairy-free recipe to exclude eggs and someone who doesn't eat gluten could make similar substitutions with the readily-available gluten-free flour that's available.
All the basic types of cake someone might be asked to produce are there (vanilla sponge, fruit cake, carrot cake, coffee & walnut etc) and there are charts for the more popular cakes that give quantities for different sizes. Revelations for me were the American frosting, which can be used to give a similar effect to covering a cake in royal icing and the vegan versions of different modelling pastes. Even better, as someone who hates marzipan, there's a nut-free alternative (though I'll be using vanilla essence as the flavouring!). There are very useful step-by-step photos to illustrate how to crumb-coat a cake, how to cover a cake with sugarpaste etc.
The last part of the book has projects, including innovative decorated biscuits, individual mini cakes and stunning wedding cakes. Finally, there are charts showing you which manufacturers' products are suitable for which diet (helpful, but readers would still need to check carefully in case a product's ingredients change).
I had a couple of questions and contacted the author through her website. She responded very promptly and gave me the answers I was looking for, so hats off to her for that.