GnuCash Documentation
There are two major GnuCash documentation packages to help users:
The Help Manual is designed to be a quick reference of how to accomplish specific tasks and how to use the features in GnuCash. The Concepts Guide is designed to be an in depth guide to the concepts behind using GnuCash with a tutorial to show how to put those concepts into practice.
Additionally, you can talk to someone via IRC at irc.gnome.org channel #gnucash about your question. Another resource is the English or Deutsch GnuCash wikis.
もしヘルプマニュアルとコンセプトガイドで疑問に対する十分な回答を得られなかった場合は gnucash-user メーリングリストに英語でメールを送ってください。私たちはあなたたちのフィードバックを求めています。あなたのコメントを通してのみ私たちはどのように文書を変更するべきか知ることができます。
GnuCash's documentation has been created by its community. See the Writing Documentation page if you are interested in contributing to this effort.
GnuCash v3 (current stable release)
Current stable user documentation
ダウンロード (Stable)

This is the latest stable release of the GnuCash documentation. Stable means that this documentation is not necessarily the most up to date but it works without any problem.
GnuCash v2.6 (old stable release)
Old stable user documentation
ダウンロード (Stable)

This is the old stable release of the GnuCash documentation, corresponding to the 2.6.21 release of GnuCash itself.
日次夜間文書ビルド
Current unstable user documentation and developer documentation
ダウンロード (Unstable)

Every night a server builds the documentation from the current contents of the GnuCash source repository. This includes the Developer Documentation from Doxygen and User Documentation for the current stable version of GnuCash.
NOTE: these documents might not be accessible from time to time because developers might be working on improvements. However they are the most up to date reference for GnuCash users.
過去の GnuCash 文書
This section contains all the older GnuCash documentation. If you are using one of these old versions of GnuCash, it is highly recommended that you upgrade to the latest stable version.
Unofficial documentation
Some people have written HOWTO guides or tutorials.
NOTE: the information presented in these sources may or may not be updated to the most recent version of GnuCash. If you are interested in doing development work on these documents, you should contact the original authors.