BTW, I did buy this, which I'll probably get to right after finishing LOTR: https://www.amazon.co.uk/Tales-Perilous-Realm-Roverandom-Classic/dp/0007280599/ref=sr_1_1?ie=UTF8&qid=1480072794&sr=8-1&keywords=tales+from+the+perilous+realm
Circling back to this, I just finished reading this book, which is made up of this collection of stories (description borrowed from Amazon):
• Roverandom is a toy dog who, enchanted by a sand sorcerer, gets to explore the world and encounter strange and fabulous creatures.
• Farmer Giles of Ham is fat and unheroic, but - having unwittingly managed to scare off a short-sighted giant - is called upon to do battle when a dragon comes to town;
• The Adventures of Tom Bombadil tells in verse of Tom's many adventures with hobbits, princesses, dwarves and trolls;
• Leaf by Niggle recounts the strange adventures of the painter Niggle who sets out to paint the perfect tree;
• Smith of Wootton Major journeys to the Land of Faery thanks to the magical ingredients of the Great Cake of the Feast of Good Children.
Out of all these, Farmer Giles was probably my favourite. The farmer finds himself as an accidental hero, after shooting a giant, and is called upon by the rest of the village to sort out a little dragon problem. That one feels the most fleshed out, and complete as a story. There's also a great sense of humour and fun as Farmer Giles uses a combination of wits and luck to get through various scrapes.
The Adventures of Tom Bombadil was a bit of a disappointment. It's told as one long poem, so it you weren't a fan of the poetry in LOTR, you'll not like this. I didn't really get to find out much more about Tom as a character, his origins, or what he was up to pre LOTR, which was a little bit of a let down.
The other stories are quirky and interesting in their own way, but there wasn't really much meat on the bones. Roverandom in particular I found pretty wacky and hard to follow. I can see why they were compiled into this book, as there's not really enough material to stand on their own as separate books.
Still, it was fun to dip into some of Tolkien's non-Middle Earth material.