Books by W. H. Lawrie worth reading.

All-Fur Flies and How to Dress Them. 1967
Border River Angling. 1939
Big Trout. 1955
English and Welsh Trout Flies. 1967
International Trout Flies. 1969
Scottish Trout Flies. 1966
English Trout Flies. 1967
Modern Trout Flies. 1972

All the above books are available at reasonable prices,
at less than GBpounds20.00 - US$31.47.

The Book of the Rough Stream Nymph. 1947
This book will be a bit more expensive GBp 30.00+ US$47.21
still worth the money.
This book and 'Border River Angling' are the two books which
expound his theories on 'surface nymphing', which is an early
form of 'emerger' fishing.
His name for an Emerger was a Hatching Dun.

The reason for all this, is my recent mining of old fishing books
on the Internet Archive http://www.archive.org/

Unfortunately Lawrie's books are still in copyright, so, no freebies.
But, they are very reasonably (cheap) from second hand book dealers.
Easy source is AbeBooks http://www.abebooks.com/
There are others Barnes & Noble http://www.barnesandnoble.com/

If you have an aversion to reading books,
you have my deepest sympathies.