Gallagher's first book on Nessie, Loch Ness: From Out of the Depths, reprinted original newspaper stories during the "rise of the Loch Ness Monster" from 1933 to 1934. This second book reprints newspaper stories from 1935 to 1955.
Here's the book description:
"The 1930s were most definitely the boom years for the Loch Ness Monster, that enigmatic cryptid which supposedly dwells in one of Scotland's deepest lakes. The imagination of the world was excited by the apparent emergence of the creature in 1933, with dozens of sightings reported by people from all walks of life. The high volume of sightings continued through 1934, making these two years the all-time peak in 'Nessie' sightings. But then, gradually, the number of reported sightings in the press began to taper off. Never again would 'Nessie Fever' grip the Scottish Highlands in quite the same way. There were occasional spikes in reports, but nothing to match those original two years. That decline is reflected in this volume, which contains original newspaper accounts pertaining to the Loch Ness Monster between 1935 and 1955."
You can get the book here.