The Routledge Dictionary of Egyptian Gods and Goddesses contains one of the most comprehensive listings and descriptions of Egyptian deities. Now in its second edition, it Presenting a vivid picture of the complexity and richness of imagery in Egyptian mythology, students studying Ancient Egypt, travelers, visitors to museums and all those interested in mythology will find this an invaluable resource.
George Hart was a British Egyptologist. He studied classics and Egyptology at University College London. He was a staff lecturer in Egypt and the classical world at the British Museum from 1973 until his retirement in 2004. In addition to his museum work, he also taught Egyptian hieroglyphs and lectured on cruises.
Those accidental finds while cruising the shelves at the library, are the best of all, when they turn out to be just right for what one needs. I have yet to tackle learning about this mythology. The helpful introduction gave me a firm grasp upon the Dynasties, and characteristics of each epoch which placed the shifts in prominence of one deity group over another make sense. This important piece to the puzzle of deciphering the centuries of mythology, clarified many questions. For that part alone, I would give this as a recommended beginning to the study. Each entry covered the basics, distinguishing fact from conjecture, and assuring to touch on the key points, and relevant information. My interests are more in the lesser known deities. I know the treatment would be brief, yet, in a tome devoted to concise articles, it is refreshing to see a few of the lesser known beings discussed. By its size, it can hardly be expected to be exhaustive, or complete. The purpose is to offer information about the most familiar characters in myth, and history.
Hart's book has entries on nearly as many gods as its competitor, Richard Wilkinson's The Complete Gods and Goddesses of Ancient Egypt. Hart covers some very minor gods that Wilkinson doesn't, and vice versa. Hart covers the major deities in more detail than Wilkinson does, but the entries in Wilkinson's book have more consistent internal organization. Hart's alphabetical arrangement is probably more convenient for most people than Wilkinson's approach of grouping deities by the form they were depicted in, though both are imperfect (many names have variant spellings; many deities appear in several forms). I favor Wilkinson's book because it says more about how deities' significance changed over time and, unlike Hart's, it has a lot of information about the general characteristics of the gods, which makes their often confusing behavior easier to understand. But you can't go wrong buying either book.
Haven't read this entire book, but I'm using it frequently as I learn about the major Egyptian gods and goddesses. This is a good reference book if you're looking for a concise introduction. The entries are short (9 pages for Amun, perhaps the most important Egyptian god), and the full book is only 187 pages. There are lots of illustrations, although in black and white. Each god/goddess also has their name indicated in hieroglyphs. There are entries on major Canaanite deities worshipped in Egypt, and a 10 page introduction describing the main sources of knowledge about ancient Egypt.