-Despite the recent progress, the corner-stone of most RAM data structures
-is still the representation of data structures by integers introduced by Fredman
-and Willard. It will also form a~basis for the rest of this chapter.
-
-\FIXME{Add more history.}
+The Fusion trees themselves have very limited use in graph algorithms, but the
+principles behind them are ubiquitous in many other data structures and these
+will serve us well and often. We are going to build the theory of Q-heaps in
+Section \ref{qheaps}, which will later lead to a~linear-time MST algorithm
+for arbitrary integer weights in Section \ref{iteralg}. Other such structures
+will help us in building linear-time RAM algorithms for computing the ranks
+of various combinatorial structures in Chapter~\ref{rankchap}.
+
+Outside our area, important consequences of these data structures include the
+Thorup's $\O(m)$ algorithm for single-source shortest paths in undirected
+graphs with positive integer weights \cite{thorup:usssp} and his $\O(m\log\log
+n)$ algorithm for the same problem in directed graphs \cite{thorup:sssp}. Both
+algorithms have been then significantly simplified by Hagerup
+\cite{hagerup:sssp}.
+
+Despite the progress in the recent years, the corner-stone of all RAM structures
+is still the representation of combinatorial objects by integers introduced by
+Fredman and Willard. It will also form a~basis for the rest of this chapter.