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Book Viewer

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The "Book Viewer" (Figure 1) is accessed via the "View Book" or thumbnail links on the Resource Record page. Only one resource may be accessed at a time. The "Book Viewer" includes various features and controls for exploring the resource.

Bookviewer display

Figure 1: "Book Viewer" Interface. The left-hand navigation panel includes the Information (A), Search Inside (B), Additional Links and Download PDF (C). The right column includes the Book Viewer features buttons (D), the page thumbnails (E), navigation and display options (F), and the "Back to Search" and "Start Over" links (G).

Left Navigation Panel

The navigation panel in the left column includes four features for exploring the resource; Information, Search Inside, Additional Links, and Download PDF

The panel may be collapsed or expanded by clicking the double arrow icons (Left arrow button or Right arrow button). When the column is collapsed, it appears as a thin, vertical bar on the left-side of the screen.

Each box within the navigation panel may be expanded by clicking the plus symbol (Plus button) to display its contents. The minus symbol (Minus button) collapses the box to display only the feature's title bar.


The "Information" (Figure 2) appears at the top of the left column and includes four metadata fields from the resource record; titles, authors, publication information, and subjects.


Figure 2: Information includes the titles, authors, publication information, and subjects.

Search Inside

Search queries are retrieved from the resource's uncorrected full-text generated by Optical Character Recognition (OCR) software. The search engine retrieves results related to queries for a single word or quoted phrases. See Searching for how to search all of the resources in the Digital Collections and Searching Video Transcripts for how to search individual videos.

For example, entering the term "operation" will return "operation" as well as "operations", "operates", and "operative" (Figure 3).  Entering a quoted phrase for "Asiatic Cholera" will return results while the same phrase without quotes will only retrieve a result if there is an exact match. Queries without any results will include the statement "No matches found."

Retrieved results include the page number and a snippet with the search term highlighted in bold.  Each result's snippet includes only the first instance of the term found on the page (Figure 3). Results are listed in order of relevance.  When you click on the individual page result, the full page will open in the right access panel.

Search inside this book

Figure 3: Search Inside with results for the query operation.

Additional Links

There are two links for accessing the resource record page or the bibliographic record in this box (Figure 4). The "Return to Resource Record" links returns to the resource's Resource Record page. The "LocatorPlus Record" link opens a new browser window with the resource's bibliographic record in LocatorPlus, NLM's online catalog.

Additional links

Figure 4: Additional Links to the Resource Record page and LocatorPlus.

Download PDF

You may download a complete copy of the resource's PDF by selecting the title link in the "Download PDF" box (Figure 5). See Downloading Resources for information on additional formats.

Dowload PDF

Figure 5: Download PDF with link to PDF file.

Viewing PDF files

If a PDF of the resource is available, it should automatically open in the Adobe® Reader in your browser window. Use the features in Adobe® Reader to view, save, or print the resource. You must install Adobe® Reader on your computer to access the PDF document.

If you use Firefox as your Web browser and you cannot view the PDF, see View PDF files in Firefox without downloading them ( or Using a PDF reader plug-in ( for more information.

Right Access Panel

The right access panel includes the "Book Viewer's" feature buttons at the top, thumbnail images of the resource's pages in the middle, and navigation controls at the bottom to navigate the thumbnail screens or individual pages (Figure 6). Select the “Back to Search” link to return the search results display. Start a new search by selecting “Start Over” and entering a new search term or phrase in the search box on the Home page.

Thumbnails view in book viewer

Figure 6: Thumbnails View in the "Book Viewer." The Thumbnails button is selected (A), the "Back to Search" and "Start Over" links (B), the thumbnails appear in sequential page order (C), and the navigation controls at the bottom automatically display 100 items per page (D).

There are seven controls for exploring the resource's pages; Pages, Thumbnails, Raw Text, Zoom In, Zoom Out, Reset Zoom, and Use Flash. The default setting is the "Thumbnails" view.


The "Pages" button displays the full-size image of an individual page. The "Pages" view may also be accessed by clicking a thumbnail image of a page to view it in full-size. Once "Pages" is selected, all of the control buttons at the top of the access panel are activated. 


The "Thumbnails" button displays the thumbnail images in a grid. The control buttons for zooming and flash are deactivated while in the "Thumbnails" view. Each thumbnail includes the sequential page number. The default display setting is 100 thumbnails per page.

Raw Text

The "Raw Text" button displays the text of the page you are viewing. The uncorrected text is generated by the Optical Character Recognition (OCR) software. It is used by the "Book Viewer's" search engine to generate results from your search queries (See Search Inside).


The "Zoom In" and "Zoom Out" buttons allow you to minimize and maximize the size of the page image using the pre-defined zoom levels. The "Reset Zoom" button returns the page image to the original image size. 

Using Flash

The "Use Flash" button enables the Flash-based zooming tool. The tool allows you to explore the page by zooming and panning. When the tool is enabled, your cursor will change to a magnifying glass (Figure 7A) and a small thumbnail image of the page (Figure 7B) appears in the upper right corner of the screen.

To access the features in the "Use Flash" control panel, hover over the thumbnail (Figure 8).  Click the "Use Flash" button again to deactivate the setting and return to the "Pages" view.

Use Flash Tool in right corner

Figure 7: The Default View of the Use Flash Tool. The cursor changes to a magnifying glass (A) and a thumbnail image of the page appears in the upper right corner of the screen (B).

The "Use Flash" control panel includes various features for manipulating the page image (Figure 8). The magnifying glass allows you to zoom into a specific location on the page and the hand tool allows you to readjust the position on the page (Figure 8A). Rotate the image using the red arrow in the dial or clicking the left or right rotation symbols to rotate by increments of ninety degrees (Figure 8B). 

The plus and minus controls and the slider (Figure 8C) zoom in and out of the page image. The cursor appears as an arrow while in the "Use Flash" control panel (Figure 8D). The location and size of the red box changes as you zoom, rotate or resize the page image (Figure 8E).

Use Flash features

Figure 8: The Use Flash Tool includes a magnifying glass and hand tool (A) and the dial and gray boxes for rotation (B) across the top. The plus and minus buttons and the slider bar (C) are located on the right side. The cursor appears as an arrow while hovering in the tool (D). The red box identifies which part of the page is being viewed (E).

Navigation Controls

The navigation controls are located at the bottom of the right access panel. The controls allow you to navigate through the thumbnail images or individual pages using the first, previous, next, and last buttons (Page navigation buttons).

Enter a different page number in the "Page" field to view a new screen of thumbnail images or a different page. The drop down menu allows you to change the number of thumbnails displayed from 100 to 200, 500, or 1,000 (Figure 9). However, it is not active when you are viewing individual pages or if there are less than 100 pages in the resource (Figure 10).

Page navigation for thumbnails view

Figure 9: Navigation controls settings in Thumbnails View.

Page navigation for pages view

Figure 10: Navigation controls settings in Pages view. The Items per page is deactivated.

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