These writers do not live in 4D nor Macintosh ghettos. Anyone still programming in version 3.5 should not feel slighted because the book covers v3.5 and v6 equally well. Throughout the book, differences between 4D 3.5 and 6 and single-user vs. 4D Server are pointed out. This makes it easier to make the transition from 3.5 to 6. 4Dv6 has transformed much of 4D's terminology to be closer to standard database nomenclature.
Files are now tables, layouts are now forms, etc.
Programming 4th Dimension uses version 6 terminology but provides a table showing the changes from the previous version. It even covers how 4D terms relate to more traditional database terms, such as primary key and second normal forms. The best method in which to write 4D code is to assume that it will be compiled and used with 4D Server. Even if you do not use 4D Server, writing code with it in mind with often result in code optimization and allow for future advancement to a multi-user database. 4D Compiler and 4D Server put certain constraints on your coding, but they result in better code.