Stripping intangibles removes the part of book value created by acquisition accounting rather than by anything saleable. For banks and asset-heavy businesses this is the standard measure; for software companies it is close to meaningless and often negative.
It is the denominator of price-to-tangible-book and the base against which banking regulators compute capital, in a modified form, as tier-1-capital.
Example: Northwind Tools has $570M of shareholders-equity, $240M of goodwill and $109M of other intangibles, so tangible book value is $221M, about $2.30 a share on 96 million shares.
Related: shareholders-equity, goodwill, intangible-assets, price-to-tangible-book, tier-1-capital