How to play against somebody using the book I’ve not been playing chess that long, but I do not understand why chess.com and lichess have this thing called the book. This allows people to cheat in my ‘book”.

I used it for a while on lichess until it dawned on me I was learning nothing and became reliant on it.

Some people I play against use it and the book is useless whenever it can’t find a match for your position. Are there any tips to disrupt somebody using the book?
The rules set by chess.com and lichess are basically the same (see this and this):

Use of computer programs or chess engines is not allowed for any kind of games. Use of (paper/e-book) opening books and games databases is allowed for correspondence/DailyChess games only.

So you cannot prevent your opponent from using an opening book. If you are uncomfortable with your opponent using help for the opening, there are a few things you can do:


ask them not to use opening books
try to play unrated games where players might be more eager to experiment (i.e. play without opening books)
don't play correspondence games, but longer standard time controls
go for sidelines that are not in the book (though that will not be good for improving your chess)


However IMO, correspondence chess is a special form of chess and the whole point there is that players get plenty of time in order to analyze the game on a board, in order to consult books, or even to use engines in some of the correspondence chess tournaments. Trying to restrict this seems kind of artificial to me. I mean, if you considered correspondence chess as just a regular game with extended time control (i.e. no external help whatsoever allowed), there is not much you gain from say having an hour per move or having a week for a move.