i don´t believe in books, i believe in good moves.
the book meeting 1.d4 by Jakob Aagard. still good?

I don't think it makes a lot of difference at the 2000-level whether or not your sources are ten years out-of-date.

I have a few of those books, Im not convinced they are worth buying.
I mean, you could download a load of tarrasch games and analyse them with an engine....

i have gm repertoire 10 from 2013 which is about the tarrasch defence and i like it. my question is about the sidelines because the book meeting 1.d4 covers pretty much every move that isnt 1.e4 everything from the londonsystem to 1.b4. its the sidelines that im wondering about the quality

I have a few of those books, Im not convinced they are worth buying.
I mean, you could download a load of tarrasch games and analyse them with an engine....
You may as well, since many opening books are datadumps. I have 1.b3 by Byron and Jacobs and it's mostly just variations with superficial text commentaries.
Aagard is a great author, he made Basic Positional Ideas and the Right Decisions Chessbase CDs. One is of course about Basic Positional Ideas and the other focuses on calculation. Both of these are at the heart of chess. There's even a technique section for playing positions against a computer, like a Petrosian game where you need to hold the draw so you could calculate your way to a great defense. That's what's great about this CD: not all exercises are about attack and win but there are some tough defensive tasks in there too.

yeah but the lines in the book is carefully selected lines to fit for a tarrasch player so im tempted to give it a shot

There is barely anything on the internet about the Tarrasch or isolated d-pawns for that matter. If you only want sidelines you can probably find comfortable positions w/o a book.
http://www.chess.com/forum/view/chess-openings/whats-wrong-with-1b4
If you wade through all the "I like it so there" posts you'll probably find something you like against 1.b4.
It's probably still good because 2002 isn't that long ago at amateur level, and especially because the kind of player that plays the Colle, London etc isn't the kind of player that's booked up with hypersharp recent novelties.
does the lines he recommend against everything but the tarrasch defence london, colle etch still hold up? it looks good but the book is from 2002 so i would like another opinion before using to much time on the lines