The ill-fated mountaineer George Mallory's only book was "Boswell the Biographer"?
Boswell in Holland 1763-64
This volume picks up where Boswell's London Journal left off, or actuallly a few days before, on August 1, 1763, shortly before Boswell's departure for Holland. It ends with his leaving Utrecht on June 18, 1764, to embark on his tour of the German courts in the company of George Keith, Earl Marischal, and Emet-Ulla de Froment.
Although the direct successor to the London Journal, Boswell in Holland is markedly different, as most of his journal from that period was lost already in his own time, as can be read in some of his later journal entries and letters (1766-67). For that reason, most of the Yale edition of Boswell in Holland consists of Boswell's daily memos written by himself to himself, recounting bits of the day before and planning the day to come. In addition to these, some of Boswell's French and Dutch themes are included. Boswell wrote them to improve his language skills, but as most of them recounts actual events and thoughts, some of them are quite nice substitutions for actual journal entries. To complete the volume, a large part of his correspondence from this period is printed, as well as some of his later correspondence with a few of the people whom he met while staying in Utrecht.
As was the case with Boswell's London Journal, Boswell in Holland was originally published by William Heinemann Ltd. in two editions: An ordinary version and a deluxe version published only in 1,050 numbered copies. However, where the deluxe London Journal includes a large journal fragment not printed anywhere else, the only addition to the deluxe version of Boswell in Holland (apart from the binding and generally better quality) is a number of pictures not printed in the standard edition. Thus, it looks better on the bookshelf, but doesn't really add anything to the story.
The standard edition was published in large numbers, probably due to the success of the London Journal. It was even translated into more languages than any other of his journals, save of course its predecessor. It can be had cheaply via the AbeBooks.com used books search engine. The deluxe version is naturally more scarce, but is still often available with prices ranging from £40 to £160.