C.S. Lewis always aimed to write enjoyable reading, and of course often succeeded. Certainly, this diary is enjoyable; there are no tedious portions to it that I can think of. It is also instructive.
One thing you will learn from it is how to lead the scholarly life, because that’s what he chronicles. In fact, his account includes a portion of his life when he was under enormous strain at home with daily life, moving, being poor, having a madman to care for for two weeks and to cap that all off, difficult examinations. Warren Lewis comments on the result of that examination as perhaps his brother’s greatest academic achievement. You can read in this book about the experiences and events leading up to it. There are sometimes mythical overstatements of the intellectual powers of C.S. Lewis. Here you get in his own words how he studied, how much he got done in a day, the sorts of setbacks and frustrations he faced.
Another thing that can be learned here and studied is his maturing attitude toward Romanticism. He had to struggle with it not only because it shaped all his moments of pleasure in nature–which delight was a constant thing for him–but also because the episode of a fortnight in close proximity with a raving demented man shook him up and made him approach Romanticism much more responsibly than he would have.
It is interesting to know that he read Richard Hooker–from whom he derives his ideas of church polity, which is important in shaping his Christian writing later on–before he returned to Christianity and for the sake of understanding the period, rather than the Anglican Church.
Much also about his friends in this book, Barfield, Greeves, Harwood, Baker. Not, alas, so much about Tolkien. It does make you wish he’d kept up the practice, but then what eventually he had to do was write letters, of which we have a good remaining amount.
I can’t help thinking, reading what is available in this journal, that I wish the biographies to date had made better use of this material.