This guide provides an important revised and updated overview of the allergy subject. Allergies of some kind affect up to 30% of adults and 40% of children worldwide. In this updated edition of our popular Guide, 8 of the most common allergies, their symptoms and foods to avoid are summarized. In addition, over 30 other less common allergies are introduced. The 1st Edition has sold thousands of copies Australia-wide since it was first published in 2014.