I won this book in a Goodreads giveaway and I found it to be interesting. The author gives a little background on how and why this topic is of interest to him then he lays out his criteria for deciding if a vision or appearance is likely valid. Whether you agree with his assessments or not you at least know how he decided whether or not to accept a vision as real.
He then relates several Biblical and Apocryphal visions and appearances not only of Jesus but also some of Mary. These descriptions vary in length from a paragraph or two to a page. Most descriptions include a short commentary on why he thinks it's believable.
The book is well referenced, though it doesn't include any weblinks. I can somewhat understand this as links move or expire and it's easy enough to do a quick websearch to find the information, but they would have been nice.
If a person in already inclined to believe in visitations from Jesus and Mary this book isn't going to do much to strengthen that belief. Nor will it change the mind of someone who believes that visitations are not real. It may sway someone on the edge of belief, mostly through providing many likely unknown visitations as well as other sources to read more in depth about them. I did learn about many visitations that I hadn't heard of before.
It's a good introductory book on this topic, providing enough examples for someone to have direction on where to look, and what to look for, in exploring further.