You may notice that when you search for this book here, or otherwise, that Philip Sidney's name comes first, or as only. But in reality, the majority of these reworked poems of the Psalms are the work of his sister, Mary (who though marriage is related to George Herbet, a distant cousin). Philip had finished, or partially-finished, only the first 43 psalms, and Mary did the rest. Her part was ignored much in Victorian times, but should be noted these days.
How many mounting wingèd tree
For traffic leave retiring land
And on huge waters busied be,
Which bankless flows on endless sand!
These, these indeed, well understand,
Informed by their fear-open eye,
The wonders of Jehovah's hand
While on the waves they rocking lie. (Psalm 107)
Here are the Psalms of the Old Testament of the Bible, turned into poetic forms of various styles, some quite delightfully clever (Psalm 55 is given a detailed look as an example in the Introduction). The result was read widely in manuscript form (of which 18 still exist), only printed first in 19th Century. It was a great influence on poets, and John Donne wrote a intro poem for it (Mary wrote the other two). There are helpful glosses and notes, a note on emendations, and a chronology of the siblings' life.
Peter wrote many other things also, and equally clever Mary worked some translations also. They lived in the time of Elizabeth I, Mary having a better luck in life than Peter (who died at 32 of gangrenous wound).
I liked getting to know some old words from their time, and some psalms stood out particularly well, like 111 being an A to U poem, 117 with its first letters of each sentence spelling their own sentence, and 119 using non-Hebrew alphabets. The Notes after the Psalms speak first generally about what each psalm is about, then explain further some meanings within each that each poet has used, or what their sources have said.
An undefilèd course who leadeth,
And in Jehovah's doctrine treadeth,
How blessed he!
How blest they be
Who still his testimonies keeping,
Do seek him with hearty seeking. (Psalm 119)
I think that one might enjoy these poems best if reading slowly, taking time to enjoy each poem-psalm, because otherwise they might blur, though they are good. This was an interesting read, and as each psalm was a poem of different type (and Psalm 119 had a different style for each alphabet's part), reading was never boring.