diff --git a/README.md b/README.md
index faa4433..7a040fa 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,7 @@ An object with the following options keys:
 * **endTime** End of time period of interest (`new Date()` object). If `endTime` is not provided, the current date is selected.
 * **geo** Location of interest (string).
 * **hl** Preferred language (defaults to english)
+* **category** Category to search within (defaults to all categories)
 * **resolution** Granularity of the geo search (enumerated string ['COUNTRY', 'REGION', 'CITY', 'DMA']).  `resolution` is specific to the [interestByRegion](#interestByRegion) method.
 
 **callback**
@@ -141,6 +142,7 @@ Requires an `object` as the first parameter with the following keys:
 * `endTime` - *optional* - type `Date` object - the end of the time range of interest (defaults to `new Date(Date.now())` if not supplied)
 * `geo` - *optional* - type `string` - geocode for a country, region, or DMA depending on the granularity required (defaults to worldwide).  For example, `geo: 'US-CA-800'` will target the Bakersfield, California, United States or `geo: 'US'` will just target the US.
 * `hl` - *optional* - type `string` - preferred language code for results (defaults to english)
+* `category` - *optional* - type `number` - a number corresponding to a particular category to query within (defaults to all categories)
 
 Optional callback `function` as the second parameter (otherwise returns a promise)
 
@@ -202,6 +204,7 @@ Requires an `object` as the first parameter with the following keys:
 * `geo` - *optional* - type `string` - geocode for a country, region, or DMA depending on the granularity required (defaults to worldwide).  For example, `geo: 'US-CA-800'` will target the Bakersfield, California, United States or `geo: 'US'` will just target the US.
 * `resolution` - *optional* - type `enumerated string` either `COUNTRY`, `REGION`, `CITY` or `DMA`.  Resolution is selected by default otherwise.  Trying to select a resolution larger than a specified `geo` will return an error.
 * `hl` - *optional* - type `string` - preferred language code for results (defaults to english)
+* `category` - *optional* - type `number` - a number corresponding to a particular category to query within (defaults to all categories)
 
 Optional callback `function` as the second parameter (otherwise returns a promise)
 
@@ -263,6 +266,7 @@ Requires an `object` as the first parameter with the following keys:
 * `endTime` - *optional* - type `Date` object - the end of the time range of interest (defaults to `new Date(Date.now())` if not supplied)
 * `geo` - *optional* - type `string` - geocode for a country, region, or DMA depending on the granularity required (defaults to worldwide).  For example, `geo: 'US-CA-800'` will target the Bakersfield, California, United States or `geo: 'US'` will just target the US.
 * `hl` - *optional* - type `string` - preferred language code for results (defaults to english)
+* `category` - *optional* - type `number` - a number corresponding to a particular category to query within (defaults to all categories)
 
 Optional callback `function` as the second parameter (otherwise returns a promise)
 
@@ -305,6 +309,7 @@ Requires an `object` as the first parameter with the following keys:
 * `endTime` - *optional* - type `Date` object - the end of the time range of interest (defaults to `new Date(Date.now())` if not supplied)
 * `geo` - *optional* - type `string` - geocode for a country, region, or DMA depending on the granularity required (defaults to worldwide).  For example, `geo: 'US-CA-800'` will target the Bakersfield, California, United States or `geo: 'US'` will just target the US.
 * `hl` - *optional* - type `string` - preferred language code for results (defaults to english)
+* `category` - *optional* - type `number` - a number corresponding to a particular category to query within (defaults to all categories)
 
 Optional callback `function` as the second parameter (otherwise returns a promise)