Not so much a discussion of individual Psalms as 12 chapters, each an essay on an aspect of the Psalms as a whole, but in the easy-reading style of Lewis's apologetics!
1. His introduction explains the style of poetry of the time, so helping the reader appreciate the psalms as poetry/song.
2. Then he covers judgement and the Jewish notion of the plaintiff before God in a civil case seeking the righting of a wrong, and the Christian concept of the sinner being judged by God in a criminal case, and how both ideas are insightful when reading Psalms.
3. He covers the 'cursing Psalms';
4. Death/afterlife;
5. Delight in God (such as made David dance;.
6. Praise for God's laws (and delight in the law: not (only) obedience, but study);
7. Connivance: hating what God hates and how we should behave in the presence of evil/wrong;
8. Nature and God: creation and creator: God as eternal, not, as in pagan lore, one who himself was formed out of chaos.
9. The idea of praising God because he wants us too: does this make God a tyrant or a insecure? No, we praise him because his Being demands it, just as good art demands a reaction. As God is perfect, we cannot critique him, so praise is his due, just like we praise the beauty of a woman or a landscape: it is a natural reaction to the sublime.
10. Creation stories in pagan cultures do not negate the verity of our God: rather they are a glimpse of truth vouchsafed to the pagans. Plato's Republic (II, 361) images a Christ-like figure: this was not coincidence, but reflects Plato's wisdom. Lewis' view of scripture as God-breathed does not mean it is a scientific treatise or handbook, but rather God has moulded the meanings of the various writers through the ages to reflect his truths.
11.Christ identified himself with the sufferer and the messiah figures in the Psalms.
12. The appositeness of the Psalms allocated to Christmas, Easter, Whitsun, etc. in the Psalter.
Seven Psalms are given entire at the end (in the Coverdale translation), and a full index of all Psalms mentioned.
Some very interesting points; I don't agree with it all, but certainly food for thought. I find with much of Lewis though, that I get 1/2 to 2/3 of the way through a chapter, then he begins to lose me with somewhat convoluted sentences and bracketed clauses. The writing might come across better orally because of this, it feels like spoken rhetoric. Certainly I had to reread some sentences several times to parse them. But overall, a highly recommended exposition and digression on ideas generated by reading the Psalms, rather than a commentary on the Hebrew original wording, or on specific Psalms. But definitely as he himself says, directed at Christians, rather than, like his other apologetics, at anyone.