I’m eager to plunge into St. Thomas Aquinas’ writings, but I’m not sure whether to start with his 3020-page Summa Theologica, or his 1310-page Summa Contra Gentiles.
Which is more difficult? Which requires more philosophical background? Does SCG cover a broad range of general topics on Christianity like ST, or is it more focused on apologetics? Which do you find more interesting? More useful?
Which would you start with?
Nothing can make St. Thomas an “easy read”. IMO, there is a lot to be said for taking him in, not (as it were) by gobbling him up in fell swoop (that would lead to severe indigestion); but, by taking him a treatise at a time, & concentrating on that. If I were a complete beginner, I would start, either with the Compendium of Theology, or, with the ST. The quaestiones in the ST are grouped in fairly self-contained treatises - for instance, the treatise on the angels is a treatise of 15 quaestiones and takes up Part 1, quaestiones 50 to 64 inclusive.
If you want some “easy” Thomism, you could try the English translation of the (unfinished) Compendium of Theology, available from Sophia Institute Press under the title “Light of Faith”. A lot of Aquinas is unfinished

- OTOH, this is a man who was the author of about a hundred works, of various kinds, in slightly over 20 years.
I prefer the ST to the SCG, simply because the ST is a bit later, and so, more likely to represent his final position. FWIW, I find it less densely written - the subdivisions of the ST, are so numerous, as to make it much easier for the reader to chew on as much,or as little, as he or she can “take”.
The SCG is apologetic in intention. The ST sets out to be an introduction to theology - but gradually, it becomes a systematic theology of the Catholic Faith. It is not complete: St. Thomas left off in the course of the treatise on penance, at Part 3, Question 90, Article 4. The rest of it, as found in the English translation on-line made by the Ottawa Dominicans in 1922 (?), is a scissors-and-paste job put together from his Commentary on the Sentences, which he had written about 20 years earlier.
There is a
lot more to him than the ST & the SCG. His Biblical commentaries are being translated; some day, in the far future, I hope to read his commentary on St. John’s Gospel. There is a massive amount of Mediaeval Biblical scholarship which is there for the reading, if only people knew about it.
BTW, it is an extremely good idea to read a biography of him. Such as that by the late James Weisheipl:
It has plenty to say about Aquinas the university professor, theologian, & philosopher, as well as the bare facts of his life.
These may be some use:
Hope that is some use.