There are a couple of indispensable books in our home right now:
Smart Medicine for a Healthier Child is the first thing I turn to when one of my girls gets sick. I love how I can look up the illness and see the detailed description (to make sure I've made the correct diagnosis!), the conventional treatment, herbal treatment, homeopathic treatment, dietary guidelines, nutritional supplements, acupressure, and general recommendations. For many, preventative measures are also listed. If you only buy one book for your family, this is it.
To supplement SMFAHC, we have "Compresses and Other Therapeutic Applications" by Monika Fingado, which lists in detail how to apply compresses. I have found this invaluable in bringing down high fevers, and it is for adults as well as children.