Unfortunately, eNotes does not currently have a study guide for the book Shockwave: Countdown to Hiroshima by Stephen Walker (maybe you could help us write one!). Shockwave is a fairly specialized book, and sort of a "study guide" to the events in Hiroshima in and of itself, so it seems to be a little difficult to find a study guide on the actual book.
Depending on what your topic is, reading other resources about Hiroshima may be of some help. Alternatively, if you are specifically looking for resources about Shockwave: Countdown to Hiroshima, you might find some answers by reading articles, interviews, and/or other websites about the book. Check out some of the links below, which include a summary of the Hiroshima timeline, an interview with Stephen Walker, and a rundown of basic information about the book.