The book Graph Databases by Ian Robinson, Jim Webber and Emil Eifrem gives an engaging overview of Graph Databases, describing typical use cases and illustrating the syntax used to construct and query them.
Graph Databases are a form of NoSQL database and, as such, differ significantly from the ubiquitous Relational Databases. The authors discuss a variety of scenarios where a Graph Database would be a better fit than a Relational Database, showing how they are particularly well suited to data which describe relationships between entities.
The book R for Business Analytics by Ajay Ohri sets out to look at “some of the most common tasks performed by business analysts and helps the user navigate the wealth of information in R and its 4000 packages.” In my opinion it succeeds in covering an extensive range of topics but fails to provide anything of substantial use to its intended audience. At least, not anything that could not be uncovered by a brief internet search.