Opening Books are small databases recording moves at the start of a game and how often each move occurs. For more information, see Book Window.
To navigate through the branches of the book one can just click on the line in the book tuning window or move around the game as usual in Scid.
To adjust the probability, e.g. rise the probability of a certain variation, one can just increase its value. Though the other values stay the same, Scid will recalculate once Save is pressed.
Scid vs. PC includes Add Line and Remove Line features. The first will add all moves (or all White or Black moves) to the current position, the latter removes all moves from then current move till the game/var end.
Due to implementation, these routines are not terribly optimal, and can be slow with large books/move sequences.
Only integer values are shown; a zero may signify that this move has a probability of less than 1%, and most likely happens with books automatically generated from game collections. One should also note that all values should add up to 100%.
For information about exporting multiple games to Polyglot Books, see the Polyglot section.
Choosing Export will export a branch of the book from the current position onwards into a single game. The continuation with the highest probability will make up the main line while all others are stored in variations. This allows for semi manually selecting lines to be included in a new book to be created. Note, that Scid can handle 3000 moves in a single game, therefore it will most likely not be possible (nor will it be very sensible) to export a whole opening book into one game. Also note that export can be done incrementally. That is, new lines are added to already existing ones. This also allows to merge several books.