There is a paragraph that mention that on Figure 4.4 "All data coming from a collection is marked in green, and all temporary data inside a Session object is colored orange." On the PDF for MEAP v11 the graphics have no color. Not sure if this is temporary and they'll eventually have colors but I'm mentioning this just in case.
Disregard. It's OK on MEAP v11.
On Listing 2.11 & 2.12 the underscore for the id is missing:

var query = { _id: ui.draggable.data('id') };

The character is there but for some reason is not visible on the PDF (at least this is the case on MAC on Acrobat DC).

It might be good to check other listings since I think the problem occurs throughout the PDF.

EDIT: I tried with Preview and it's looking OK. Seems to be a problem with Acrobat.
I finished reading chapter 5 and I have some concerns.

After creating and testing all the code, seems reactivity only works in a "per session" basis. If I have to 2 browsers opened on a given house and modify the house in any way (add a plant, delete a plant, etc), the 2nd browser is not updated automatically and I have to force a refresh to get the changes. Is this how it should work?

I think that content doesn't get updated because it's using a local copy of the object, but I'm not sure if this is something I would like to see on a modern real time app. Let's say that Guy #1 open a browser on Stephan's house. Suddenly, the phone rings and this person leaves for 15 minutes. In the meantime, Guy #2 opens Stephan's house page on another browser and start modifying it. Guy #2 can even delete Stephan's house and Guy #1 won't even know about it until he refreshes the page. Most important, after Guy #2 deletes Stephan's house, Guy #1 can still edit it and if he clicks on Save, Stephan's house will re-appear on the DB.

Is this the intended behavior?
Is there any reason why you look for the index on the fieldset instead of adding it to the actual button?

You are using:
...
<fieldset id="plant-{{index}}">
...

...
var thisPlantIndex = $(evt.currentTarget).parent().attr("id").split('-')[1];
...


Wouldn't it be easier to add the index to the button so you don't have to deal with parent() and split()?
...
<button class="removePlant" data-index="{{index}}">Remove Plant</button>
...

...
var thisPlantIndex = $(evt.currentTarget).attr("index");
...

Wouldn't it be better to use "house" or "houses" instead of "houseNameId" for the helper name? I mean, if the there are more attributes it wouldn't make sense to use "houseNameIdAddressCityZip".

Let me know if I'm being too picky on commenting on this kind of stuff and I'll just post on mayor issues.

On the other hand, is there any difference on "return HousesCollection.find()" VS "return HousesCollection.find({}, {});"?

Edit: I spoke too soon. I see the helper's name makes sense on listing 4-9.
On this code it's the first time that a Console.log is used on the server. For someone that've never used Meteor, this concept of a Server Console.log might seems strange at first since we are used to always using this command on the client. It might be wise to explain this in a new topic #E.
Not sure if it's just me, but I think the Custom Block Helpers section is really hard to understand as it is. I had to look for info about Block Helpers from other sources to understand the concept. Also, on Listing 3-14 #A it talks about a purpleBox that doesn't appear on the code.
A suggestion would be to use a sample where the word Block doesn't appear everywhere on the code to make it more clear which one is the actual Block Helper.
On heading 2.3.3 there is a paragraph that reads:
Remember what happened when you clicked the button? I told you there was some event binding somewhere, because if you click it and the ‘click’ event is fired there is a console log that prints out “You pressed the button”.

There is no console log when the click is fired. The only thing that happens is that the counter is increased by 1.

On the other hand, the beginning of this chapter has a lot of duplicated content with the helloWorld sample from the previous chapter. Is it really necessary to explain all the concepts again?

Loving the book so far!