The arrangements in Folk in Harmony were made at the suggestion of David Burleigh who thought that it might help some beginning pipers to play with a piano accompaniment to "keep them going". The tunes in Book 1 are some that a new player might expect to manage in their first year.
There is a certain amount of crossover of tunes with books 1 and 2 of The Piper's Companion - but the difference here is the piano accompaniments.
The books come with two inserts - the first is in a key for the pipes (everything, in fact, is in G) while the second is transposed for other instruments such as flute, recorder, violin, etc.
The inserts include optional seconds (which do not appear in the piano book).
From Book 1: piano part

From Book 1: insert

From Book 1:

More coming soon
Folk in Harmony Book 1
My Home · When the Battle’s O’er · The Rowan Tree · Morag of Dunvegan · Leaving Lishmore · Queen Mary · Believe Me · Chevy Chase · Winster Galop · Flett from Flotta · The Road to Dundee · 51st Highland Division ·
Hector the Hero · Loch Rannoch · Mrs Jamieson’s Favourite · Lord Lovat’s Lament · The Piper’s Weird ·
The Cradle Song · The South Wind
Folk in Harmony Book 2
Whittingham Green Lane · Sweet Hesleyside · The Herd on the Hill · Noble Squire Dacre · Jimmy Allen ·
Because he was a Bonny Lad · Gentle Maiden · The Sally Gardens · Roddy McCorley ·
Derwentwater’s Farewell · Swindon · Sir John Fenwick’s the Flower amang them all · The Redesdale Hornpipe · Buttered Peas · Proudlock’s Hornpipe · Nancy Till