Opening Books are small databases recording moves at the start of a game
and how often each move occurs. Scid's
Scid uses the popular Polyglot book format, and comes with a few databases already installed, including gm2600.bin and Elo2400.bin.
In Scid vs. PC, two books can be viewed at once. Normally, moves are listed in order of frequency, but selecting the Alphabetical box will sort them; placing like moves side-by-side.
Scid also has an Opponent's Book. [todo ???] and Book Tuning feature.
Scid comes with an altered version of Polyglot. The below features require the full version of the command line tool.
First, remove games with non-standard starts.
These can be found by searching for games with the "non-standard start" flag.
Then, negate the filter, export the games to PGN, and from the command line:
polyglot make-book -pgn GAMES.PGN -bin BOOK.BIN -min-game 1 -max-ply 30
See the polyglot documentation for more options.
polyglot merge-book -in1 w.bin -in2 b.bin out book.bin