Who Else Writes Like...?: A Readers' Guide to Fiction Authors
Both of these books are published in the UK, but they both include major U.S. authors. I found all of the authors I was looking for when using them for real readers advisory. There are plenty of authors I've never heard of in both books, but again - I found all the major U.S. authors I was looking for, so I didn't see that as a negative.
I love the format of this book. It is alphabetical by author's last name. When you look up Picoult, for example, it simply lists similar authors. All of the authors listed under Jodi Picoult (at least, those I've heard of) seem like perfectly good choices. They're similar in style and genre, mostly - not necessarily subject matter. I tend to recommend authors more on style and genre than on plot, so that's another positive.
The book also points out which books are good crossovers for teens and adults and whether the author also writes for children. Prizes won by the author are listed. In addition, it lists popular characters in series by that author. One of my favorite features of each entry is that it gives both genre and sub-genre when there is one. Under the Ellis Peters entry (shown below), it lists the genre as "crime" and the sub-genre as historical-Medieval. The nationality of the author and the author's birth/death dates are also listed.
At the back of the book are sections for "Environments" (settings), "Classic Authors," a list of characters and series, and a list of crossover authors.
I usually see readers advisory as a more organic, in-the-moment discussion with a patron, but sometimes you just can't come up with similar authors. This is a quick list, if less robust than databases like Books and Authors or NoveList. Sometimes a quick list is just enough. Sometimes patrons want to browse something like this, and if they're not computer-users they might appreciate having a book like this available.
Here's the page that includes Jodi Picoult:
Who Next...?: A Guide to Children's Authors
This is basically a children's literature version of "Who Else Writes Like...?" It is organized much the same, as you can see in the sample page below. Again, there were plenty of major U.S. authors listed, and the read alikes seemed like good choices.
However, the A-Z author section is organized by age group. There are authors A-Z and read alike authors for ages 5-7, 8-11, 12-14, and 14+. Once you go through the A-Z sections on authors, it then has over 30 pages organized by genres and themes. Want books about "friends?" Page 211 has a long list of authors that write about that topic, further broken down by the same age groups listed above. I also love that the book includes graphic novels and short stories.
Here is the page that includes popular authors like Terry Pratchett and Philip Pullman:
Over all, both books are highly recommended for library reference collections. They are organized in a simple way that teachers, parents, and even kids will be able to use it. Sometimes I find directories in reference collections that push the limits of my MLIS to figure out how the information in them is organized. These are both nice and usable.
The only real problem I see with either of these is availability in the U.S. The children's title is available through Amazon under $50, but "Who Else Writes Like...?" does not seem to be available there in its most current edition. I did not check various U.S. vendors like Baker & Taylor or Ingram.