Many books are divided in Partsparts. In some titles even a Part can be , parts are divided into (sub-)parts. Often these Parts only parts have a only title and no further content. In those cases, an empty part page can be at brill.com is avoided by leaving out idthe @id-attribute in the <book-part>-element. If the id-attribute is included, an empty part page is presented at brill.com. See for example I Kollektive: Tumult, Aufstand, Avantgarde in: Im Gedränge (brill.com). The corresponding xml XML for this part is: 

<book-part book-part-type="part" seq="2" id="BP000006">
	<book-part-meta>
		<title-group>
			<label>I</label>
			<title><italic>Kollektive: Tumult, Aufstand, Avantgarde</italic></title>
		</title-group>
	</book-part-meta>
...

...

Value without Fetish – Uno Kōzō’s Theory of ‘Pure Capitalism’ in Light of Marx’s Critique of Political Economy | Brill, is an example in which the id-attribute is not used in combination with book<book-part book-part-type="part">. The Part-titles are included in the table of contents on the landing page of the title as well as in the table of contents in the right column, but these are not clickable. The corresponding xml XML for the first part: 

<book-part book-part-type="part" seq="1">
	<book-part-meta>
		<title-group>
			<label>Part 1</label>
			<title>The Method of <italic>The Critique of Political Economy</italic></title>
		</title-group>
	</book-part-meta>

...

1. Parts can be nested. In case of a part within a part the <book-part book-part-type="part"> can be used again. Do NOT use other values such as subpart. These are not recognized at brill.com
2. If the part-page contains more information than a title, the id-attribute should be added to the <book-part>-element to show this information in xml XML and pdf PDF format.