Just do what you do now, don't buy chess books, and invest in one opening for white and one for black, you don't need to know it through and through, it's just practical to have knowledge about the opening you play.
I disagree with this, buying a good strategy book will be helpfull. When I was a beginner, I never solve chess puzzle books, all I read are strategy books. I play few games for one year OTB then stop playing. Then when I returned to play many years ago, I reached 1600 in FICS(then I stop playing again and return playing here in chess.com)..
You read chess strategy books as a beginner. Cool. Looking back, what strategy books helped you out the most as a beginning chess player? Thank you!
The strategy book that helped me improve is Winning Chess Strategy by Seirawan. I also read Planning by Mc Donald,Winning Chess Brilliancies by Seirawan and ABC of Chess by Pandolfini..These are my strategy books many years ago..
Thanks for the book titles on strategy. I am reading Pandolfini's Ultimate Guide to Chess. It's a great little, easy to read and understand book. The format is Student-Teacher.
Example
Student: Hold on for a bit. I'd like to go back to the point where you recaptured with your b-pawn on c6. That creates an isolated a-pawn for Black. I know we talked about a similar variation in an earlier lesson, but would taking back with the d-pawn, 6...dxc6, really be that bad here?
Teacher: Taking back with the d-pawn would avoid the a-pawn's isolation, but it would still lead to a problem.
More back and forth talk, and now it gets very interesting for me.
Student: ...Even though 6...dxc6 7.Qxd8+ Kxd8 denies Black the right to castle, doesn't it leave Black's pawn structure a little healthier?
Teacher: In a way, insofar as it keeps his queenside pawns together in one mass, on a7, b7, c7, and c6, so that they could conceivably defend each other. And it's true that taking toward the center, 6...bxc6, would isolate the a-pawn, so that no other Black pawn could guard it, if protection were needed. But even so, it's dynamically better for Black to accept this a7-weakness in favor of what he does get: the retained ability to castle on the kingside; greater control of the center, because he has more pawns attacking central squares; and a semi-open b-file that could then be used for attack, especially by Black's a8-rook once it moves to b8.
Student: Holy Cow! There's so much to think about.
Pandolfini goes into talking about seeing the board split in half, queenside and kingside, with White having a kingside pawn majority, and Black having a queenside majority, and here is the best part: after playing 6...bxc6, there's no way for White to create a passed e-pawn by force, because Black's d-pawn is able to control squares on the e-file that White's e-pawn must still pass over.
Wow! That is a long term strategic plus that Black has taken care of by playing 6...bxc6. So, 6...dxc6 is a positional mistake/blunder, that was from a simple recapture! To think of all the positional blunders I make in any one game!
My games are played mostly with pieces, with very little thought placed on pawns. My focus is to win a piece, not a pawn, so I look for squares for my pieces that increase my chances of winning material with a tactic.
I know zip when it comes to pawns! 
My knee-jerk reaction, is yes.
But then I realised there's a problem with that answer.
The problem is that I mean opening theory, but I think the OP may mean opening lines.
Opening theory is deeply connected to understanding positional chess. The new Move by Move series of books by Everyman highlights the study of specific openings by asking positional and tactical questions about the opening.
One cannot play good openings without either rote memorization or understanding the ideas behind the openings. Study the ideas behind the openings and you will begin to understand both the openings and the positions that arise from those openings.
Shereshevsky wrote a brilliant excursus on the endgame by focusing on the types of endgames likely to arise from specific openings. Take a look, some time, at Endgame Strategy by Shereshevsky for an idea of how important the openings really are.
I don't think that word means what you think it means. Time to break out the dictionary.