I have the following tikz code:

```
\begin{tikzpicture}[->,>=stealth',level/.style={text width=2cm, level distance = 2.8cm,level 1/.style={sibling distance=4cm},
level 2/.style={sibling distance=2.5cm}, 
level 3/.style={sibling distance=3.5cm}, }] 
\node[text width=2.5cm]  {{\em The Book Thief}\\1939}
 child{ node [text width=2.5cm] {{\em The Great Train Robbery}\\1855} 
      child{ node[text width=2.5cm]  {{\em Ross Poldark}\\1782} 
      child{ node[text width=2.5cm]  {{\em A Tale of Two Cities}\\1755}
      child{ node[text width=2.5cm]  {{\em Girl with a Pearl Earring}\\1664 }}
      child{ node[draw=none]  {{}} }
 }
      child{ node[text width=2.5cm]  {{\em The Revenant}\\1823} }
}
      child{ node[draw=none]  {{}} }
      }
      child{ node[text width=2.5cm]  {{\em The Lion, the Witch, and the Wardrobe}\\1940}
      child{ node[draw=none]  {{}} }
      child{ node [text width=2.5cm] {{\em The Life of Pi}\\1976}
      child{ node[draw=none]  {{}} }
      child{ node[text width=2.5cm]  {{\em Gravity's Rainbow}\\1944} }                            }
  }
; 
\end{tikzpicture}

```

It produces the following tree:

[![enter image description here](https://i.stack.imgur.com/lbYOe.png)](https://i.stack.imgur.com/lbYOe.png)

This isn't what I'm looking for - I want the root to be the centre of the page and it's children to be equal amounts to the left and right of it. My root note is currently too far left (this is also true for nodes further down the tree).

How can I enforce a nodes children being equally distant horizontally?

EDIT: example in full context, as sensibly requested, thank you understanding the whole 'wall of code'.

```
\documentclass[12pt,a4paper]{book}
\UseRawInputEncoding
\usepackage{tikz}
\usetikzlibrary {positioning}
\usetikzlibrary{trees}
\usetikzlibrary{arrows}
\usetikzlibrary{calc,trees,positioning,arrows,chains,shapes.geometric,%
    decorations.pathreplacing,decorations.pathmorphing,shapes,%
    matrix,shapes.symbols}

\begin{document}
\tikzstyle{every node}=[draw=black,thick,text centered,anchor=west,text width=2.4cm]
\tikzstyle{selected}=[draw=red,fill=red!30]
\tikzstyle{optional}=[dashed,fill=gray!50]
\tikzset{
>=stealth',
  invis/.style={
    rectangle, 
    rounded corners, 
    % fill=black!10,
    draw=white, very thick,
    text width=4em, 
    minimum height=2em, 
    text centered, 
    on chain},
  punktchain/.style={
    rectangle, 
    rounded corners, 
    % fill=black!10,
    draw=black, very thick,
    text width=5em, 
    minimum height=2em, 
    text centered, 
    on chain},
  line/.style={draw, thick, <-},
  element/.style={
    tape,
    top color=white,
    bottom color=blue!50!black!60!,
    minimum width=4em,
    draw=blue!40!black!90, very thick,
    text width=5em, 
    minimum height=2.0em, 
    text centered, 
    on chain},
  every join/.style={->, thick,shorten >=1pt},
  decoration={brace},
  tuborg/.style={decorate},
  tubnode/.style={midway, right=7pt,draw=gray!01,ultra thin},
}

%The Books
\begin{figure} 
\tikzstyle{fade}=[dashed,fill=gray!20]
\begin{center}
\begin{tikzpicture}[->,>=stealth',level/.style={text width=2cm, level distance = 2.8cm,level 1/.style={sibling distance=4cm},
level 2/.style={sibling distance=2.5cm}, 
level 3/.style={sibling distance=3.5cm}, }] 
\node[text width=2.5cm]  {{\em The Book Thief}\\1939}
 child{ node [text width=2.5cm] {{\em The Great Train Robbery}\\1855} 
      child{ node[text width=2.5cm]  {{\em Ross Poldark}\\1782} 
      child{ node[text width=2.5cm]  {{\em A Tale of Two Cities}\\1755}
      child{ node[text width=2.5cm]  {{\em Girl with a Pearl Earring}\\1664 }}
      child{ node[draw=none]  {{}} }
 }
      child{ node[text width=2.5cm]  {{\em The Revenant}\\1823} }
}
      child{ node[draw=none]  {{}} }
      }
      child{ node[text width=2.5cm]  {{\em The Lion, the Witch, and the Wardrobe}\\1940}
      child{ node[draw=none]  {{}} }
      child{ node [text width=2.5cm] {{\em The Life of Pi}\\1976}
      child{ node[draw=none]  {{}} }
      child{ node[text width=2.5cm]  {{\em Gravity's Rainbow}\\1944} }                            }
  }
; 
\end{tikzpicture}
\end{center}
\caption{Food}
\label{rewrite} 
\end{figure}

\end{document} 

```