A short book, and shorter than it appears: The poems selected are presented in facsimile medieval Welsh, typeset medieval Welsh and English. Of course, if you can read the Welsh version (I can't) then you'll get more out of it.

Pennar's introduction gives essential information on Taliesin, the kingdoms of 6th-century north Wales and England and historical and cultural context for the poems.

The poems themselves give a fascinating insight into a sparsely documented era, and one which was the foundation for later Arthurian legends. It's not likely you're going to be quoting any of these lines, though it might be fun to try to work:
And until I am old and ailing
in the dire necessity of death
I shall not be in my element
if I don't praise Urien
into a conversation.

Update: On my third reading, I was struck more by the power of Taliesin's verse. Although I didn't find it much more quotable, given that I'm rarely preparing for hand-to-hand combat with the villagers up the road, I seldom rustle cattle these days, nor am I often needing to praise a king for his battle prowess, there is something stirring in Taliesin's declamations of King Urien's might, pre-eminance and generous openhandedness. By contrast, the poem, What if Urien were Dead, is quiet, imbued with the poet's anxiety for the safety of the king, whose extended absence on campaign seems to me to speak of a deeper friendship and companionliness than simply that of a an artist for his patron, or of a subject for his ruler.

I think that's what brings the poems alive - Taliesin speaks directly, often in the first person, of the things he's seen and heard, tells of his own observations and feelings. He's immediate and, despite the hyperbolic agrandisment of his subject, there's an honesty to what he says. I get the strong feeling of a deep affection and friendship, not without its fallings-out and reconciliations (the latter, Pennar says, becoming a particular type of Welsh poetry, copied by later bards from Taliesin's example) between the two men. ( )