  A surface pair $(X,C)$ is a germ of a normal surface singularity $(X,0)$ and
a sum $C=\sum c_iC_i$ of curves on $X$, with $c_i\in [0,1]$. An orbifold pair
has $c_i=1/n_i$, as intersecting with a small sphere gives a $3$-dimensional
orbifold $(\Sigma, \gamma_i,n_i)$. There are natural notions of morphism and
log cover of surface pairs. We introduce a volume $Vol(X,C)$ in $\mathbb
Q_{\geq 0}$, computable from any log resolution, analogous to that in our 1990
JAMS paper when $C=0$. Denoting $\bar{C}=\sum (1-c_i)C_i$, one has $(X,C)$ log
canonical iff $Vol(X,\bar{C})=0$. The main theorem (5.4-5.6) is that $Vol(X,C)$
is ``characteristic'': if $f:(X',C')\rightarrow (X,C)$ is a morphism of degree
$d$, then $Vol(X',C')\geq d\cdot Vol(X,C)$, with equality if $f$ is a log
cover. We prove (6.7) that $Vol(X,\sum (1/n_i)C_i)=0$ iff the associated
orbifold has finite or solvable orbifold fundamental group, and these are
classified. In (8.2) is proved a key case of the DCC Volumes Conjecture: The
set $\{Vol(X,\sum (1/n_i)C_i)|\ X\ \text{RDP}\}$ satisfies the DCC, with
minimum non-$0$ volume 1/3528.
