The Bookman is the oldest portable dedicated eBook device and it is still being sold today. It is made by Franklin Electronic Publishers, Inc.
The BOOKMAN was introduced as a Bible reading device in 1989. They continue to produce dedicated portable reference devices with different eBooks preloaded but the Bible version continues to be the best seller. This device should not be confused with the Franklin eBookMan which has been discontinued. The primary focus of this product is for reference books including Bibles, dictionaries, translation features, and other reference text.
The Bookman uses plug in cards (called Bookman cards) to hold additional reference books and contains a small keyboard for searching content.
 Family of products
The Bookman is not a device but a full family of devices. Individual versions have been discontinued but the line continues. The basic common capability is to be able to use the add-on Bookman cards. A keyboard is also a key feature that contains a key to bring up the card and 4 customizable keys (colored read, green, yellow, and blue) to provide access to special features in the eBook on the card. They are also used on the internal eBook as well.
The family features include a menu system that provides access to the table of contents. It also includes utilities to provide user customization. The font size is customizable in 3 different sizes. The smallest size provides 4 lines of text on the basic units and 8 or more lines on the more advanced models. Similar the medium size starts out with 3 lines and the large text has 2 lines. There is usually not a backlight and battery life is excellent. The screen has high contrast so it can be read even without intense lighting. The screen resolution is pretty low with pixels being quite visible.
The search function allows searching through the entire book. It features a previous and next key to move through the search results. It also uses the menu system based table of contents to filter the entries to show only sections that contain the word. A more feature is present to allow matches to derived words such as plurals.
The basic model usually includes one Book, usually a Bible or Dictionary, but advanced models provide several additional features such as calculators and even simple games. Bookman products are also available under other brand names but the bookman card slot identifies them as being from Franklin. Current models include TTS voice prompting capabilities such as talking dictionaires. This can be especially handy when used with translation dictionaries.
Bookman devices are reasonably rugged and can be used by children. They generally have 2 to 4 AAA batteries that last a long time. Some models can support an AC adapter but this will generally not charge the internal batteries.
 Bookman cards
Bookman cards retail for about $10 and up with most eBooks costing between $20 and $30. They will typically work with any of the Bookman models but not all features can be supported in all models. For example a talking dictionary will only be able to talk on devices that support the talking feature but the dictionary lookup will work on other devices as well.
Some cards will interact with the base book that your Bookman came with. This can be important in picking the original device. Some cards also support primitive graphics to enhance the reading experience primarily for children.
Bookman also sells a blank card that you can use to add your own books or buy books from Franklin for less money that can be loaded on your card. Note that only some devices have the feature to allow you to add your own content to the card which also requires a computer connection. At one point Franklin had an independent product that could write the cards but it seems to be no longer available.
 The Bookman web site
The Franklin web site can be a bit confusing if you are looking specifically for Bookman products. The best way to use the site is to search specifically for Bookman or Bookman cards. They also have several hardware devices that are not bookman compatible in each of the category of products they sell. Look for the Bookman card extension feature to ensure the device is actually a bookman.