Tree Notebook is a hierarchical notes manager designed for keeping personal information.

Tree Notebook runs on an iOS device (iPhone or iPad). Besides, there is a counterpart for OS Windows which can be synchronized with up to three iOS devices via a local Wi-Fi network.
No access to Internet is needed for synchronizing.

The data in Tree Notebook is divided in two parts: the public part accessible without password and the encrypted private part which requires password for opening.

The data in every part is arranged as a tree-like multilevel hierarchy of folders and notes.
Any folder can include notes and other folders, and so fourth.
Any item (a note or a folder) can include text of any size. The items can keep attachments like images or other files.

The app can represent data in several ways: as a tree, as a list of items (folders and notes) on the current level, as a list of manually selected items ("Favorites"), or the items visited recently ("History"). The contents of an individual item can be viewed or edited.

Tree Notebook includes powerful search facilities: simplified or conditional global search, local search inside an item text.

The items can be sorted by several criteria: alphabetically, by creation or modification time, and in manually defined order. The item titles can be attributed using a variety of font types, colored flags, graphic icons.

Any item can have an Event attribute and serve as an alarm clock or reminder.
A calendar feature is available to help managing events.

The app is free to use both on iOS devices and desktop PC.