This is the new developer and design manual for GnuCash.
The documentation is organised in a rough sequence:
Please refer to the main documentation page on the gnucash website which includes links to the GnuCash Manual and the Concepts Guide in various formats.
There is also the "GnuCash Design Overview" which can be generated from the source using texi2html from the texinfo files in src/doc/design, but this is even more outdated.
Where possible, each overview is dated - take care to review older texts in relation to existing code.
Each overview in this section is generated directly from the source files using Doxygen but some topics need updating.