Mainly just to corroborate the previous reviewer, since there is just the one review of this superb double cd Traffic retrospective. This is definitely THE compilation to go for, rather than the "Best Of Traffic". That particular item dates back to about 1970 and has a running time of only some forty minutes. This far-superior double renders the other compilation practically obsolete.
The first disc of "Smiling Phases" draws in the early non-album singles, big chunks of the first two albums and a few bits of stuff from "Last Exit". The second disc features more than half of the folkier "John Barleycorn Must Die" and half of "Low Spark Of High-Heeled Boys". The latter's great title track is included in all 11 minutes 35 seconds of its splendour. The quality dips a little at the end, with one track from "Fantasy Factory" and a couple from "When The Eagle Flies". (Although an ex-girlfriend definitely wouldn't agree with my assessment of "Walking In The Wind", which is her favourite Traffic track in the whole world. Ever.)
All in all, therefore, quite fabulous value-for-money. And another good demonstration of a record company succeeding in putting out a product which is designed to satisfy. (Rather than sneakily holding back on one or two choice tracks.)