I've just read an article and saw this sentence:

Hence, characterization of squat cracks is of particular interest for this research.

Why is there a of? If I restructured this like "... cracks is particular interest for this research" what would change?

There is another sentence like this:

To study the nature of RCF defects and their behaviors, it is of great value to characterize the crack geometry.

Maybe of is used for possession but I can't understand the relation.

  • cracks is plural, BTW, so the verb needs to agree in number, are not is.
    – TimR
    Jul 24, 2018 at 12:19
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    but the whole sentence is "characterization of cracks is ..." because of that I think "is" is correct. Jul 24, 2018 at 12:33
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    @ Alperen koç: Unquestionably. The underlying grammatical subject of your text is (singular) characterization, so the verb form must be is, not are. Jul 24, 2018 at 14:22
  • Sorry, I thought you were trying to restate the sentence like this: "cracks is particular interest for this research" making "particular interest" a noun-phrase rather than a prepositional phrase complement of the verb.
    – TimR
    Jul 24, 2018 at 16:19
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    @dan It is kind of fatigue which take place in railway rails and is like a corrugation. Its shape is like that somebody sitting on the rail or squatting on the rail. Jul 25, 2018 at 10:50

3 Answers 3


This construction X is of Y can be useful if you want to concisely qualify the interest, value, etc. with an intensifier.


This book is of great interest to scholars in the field

which equals

This book is very interesting to scholars in the field.

“of little interest” equates to “is not very interesting”. It does not equate to “is not interesting”, nor to “is uninteresting”: that would be expressed as “is not of interest”.

“of very little interest” roughly equates to “is very uninteresting indeed”, or “is extremely uninteresting”.

You can, however, go one further and say “…of very little interest indeed”, which means something like “…is not interesting in the slightest”.

It would be unusual to use small here: …of small interest. That feels correct but very literary. Conversely, you can say “…of big interest” in speech, but perhaps not in writing: it feels clumsy. You can say …of huge | massive interest (in speech), you would be unlikely to say …of tiny interest (avoid).

You may have noticed that it's probably easier to figure out these variants:

of interest,
of great interest,
of little interest,
of very great interest,
of very little interest

and these negations

not of interest,
not of great interest,
of not great interest (literary),
of not very great interest (literary),
not of very great interest

than it is to figure out these equivalents

very interesting,
not very interesting,
extremely interesting,
extremely uninteresting


not very interesting,
not very interesting,
really not very interesting
not very interesting at all

The pattern I have shown for of interest and its variants can be directly applied to

of value, of worth, of importance, of note [notable, noteworthy], of concern [concerning].

However, to work out the adjectival forms of those attributes or characteristics is sometimes trickier and less regular: for example, there is no commonly used word unvaluable (avoid). Although it is in the dictionary I have never heard or seen it used: you would normally say

not of value or lacking in value, it lacks value, it has no value.

(Note that invaluable means "so valuable that you cannot count its worth", "extremely valuable".)

So the good news is that you can always use a very regular pattern for of Y and its qualified variants and their negations.

The bad news is you may sound a bit like you're talking like a book, or like someone from the 1950s. But you will sound like you are well-educated :-).

My final comment would be: you can't use this construction with any noun that could be considered to be an attribute of the thing X. This goes to the earlier observation that Y must be an abstract noun

  • This book is of cost (incorrect)
  • This book is costly (correct)
  • This book is of great weight (incorrect)
  • This book is very heavy (correct)
  • This book weighs a lot (correct)
  • I deleted the short paragraph about "worthy" (= honorable) because it is a side issue, and the answer was already quite long enough. However, if you find the edit to be too invasive, you can roll it back any time you want.
    – Mari-Lou A
    Jul 25, 2018 at 9:58

Words like interest, value, importance are abstract nouns representing "attributes, qualities" that something might have.

The construction X is of Y (where Y is a noun as per above) asserts that X has the attribute associated with the specified noun. It wouldn't normally make logical or syntactic sense to assert that X actually is that attribute (as a noun).

So you must either convert the noun to an adjective (interesting, valuable, important) or precede the attribute noun by of to indicate that there is an "association" between the subject of the sentence and the attribute specified.

Almost as an aside I should mention that many learners get confused by how of and the "Saxon Genitive" (possessive apostrophe) work in English. I'm sure there will be a dedicated question about this somewhere on ELL, but for now I'll just make the point that such usages cover a broad span of senses including "association" as well as "ownership".

That same broad span of meanings can also be partly covered using the construction to have X (again, where X is an "abstract attribute" noun as above), so we can use any of these related/equivalent forms...

This answer is of value
This answer is valuable
This answer has value
This answer's value lies in its simplicity 1

Idiomatically, some of those forms work better that others in certain contexts, or with certain types of attribute, but syntactically and semantically they're all effectively equivalent and interchangeable.

1 Kudos to @Keven for suggesting that excellent final "Saxon Genitive" example.


When {something} is of interest to {someone}, {someone} finds {something} worthy of further attention or investigation.

of interest = worthy of (further) attention or investigation

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