XPath to locate a cell with specific text parsing HTML tables

Use this XPath:

//td[contains(., 'Chapter')]

You want all tds under your current node -- not - all in the document as the currently accepted answer selects.

Use:

.//td[.//text()[contains(., 'Chapter')]]

This selects all td descendants of the current node that are named td that have at least one text node descendant, whose string value contains the string "Chapter".

If it is known in advance that any td under this table only has a single text node, this can be simplified to just:

.//td[contains(., 'Chapter')]